High availability for SAP HANA on Azure VMs on SUSE Linux Enterprise Server

To establish high availability in an on-premises SAP HANA deployment, you can use either SAP HANA system replication or shared storage.

Currently on Azure virtual machines (VMs), SAP HANA system replication on Azure is the only supported high availability function.

SAP HANA system replication consists of one primary node and at least one secondary node. Changes to the data on the primary node are replicated to the secondary node synchronously or asynchronously.

This article describes how to deploy and configure the VMs, install the cluster framework, and install and configure SAP HANA system replication.

Before you begin, read the following SAP Notes and papers:

• SAP Note 1928533. The note includes:
  • The list of Azure VM sizes that are supported for the deployment of SAP software.
  • Important capacity information for Azure VM sizes.
  • The supported SAP software, operating system (OS), and database combinations.
  • The required SAP kernel versions for Windows and Linux on Microsoft Azure.
• SAP Note 2015553 lists the prerequisites for SAP-supported SAP software deployments in Azure.
• SAP Note 2205917 has recommended OS settings for SUSE Linux Enterprise Server 12 (SLES 12) for SAP Applications.
• SAP Note 2684254 has recommended OS settings for SUSE Linux Enterprise Server 15 (SLES 15) for SAP Applications.
• SAP Note 2235581 has SAP HANA supported Operating systems
• SAP Note 2178632 has detailed information about all the monitoring metrics that are reported for SAP in Azure.
• SAP Note 2191498 has the required SAP host agent version for Linux in Azure.
• SAP Note 2243692 has information about SAP licensing for Linux in Azure.
• SAP Note 1984787 has general information about SUSE Linux Enterprise Server 12.
• SAP Note 1999351 has more troubleshooting information for the Azure Enhanced Monitoring Extension for SAP.
• SAP Note 401162 has information about how to avoid "address already in use" errors when you set up HANA system replication.
• SAP Community Support Wiki has all the required SAP Notes for Linux.
• SAP HANA Certified IaaS Platforms.
• Azure Virtual Machines planning and implementation for SAP on Linux guide.
• Azure Virtual Machines deployment for SAP on Linux guide.
• Azure Virtual Machines DBMS deployment for SAP on Linux guide.
• SUSE Linux Enterprise Server for SAP Applications 15 best practices guides and SUSE Linux Enterprise Server for SAP Applications 12 best practices guides:
  • Setting up an SAP HANA SR Performance Optimized Infrastructure (SLES for SAP Applications). The guide contains all the required information to set-up SAP HANA system replication for on-premises development. Use this guide as a baseline.
  • Setting up an SAP HANA SR Cost Optimized Infrastructure (SLES for SAP Applications).

Plan for SAP HANA high availability

To achieve high availability, install SAP HANA on two VMs. The data is replicated by using HANA system replication.

The SAP HANA system replication setup uses a dedicated virtual host name and virtual IP addresses. In Azure, you need a load balancer to deploy a virtual IP address.

The preceding figure shows an example load balancer that has these configurations:

• Front-end IP address: 10.0.0.13 for HN1-db
• Probe port: 62503

Prepare the infrastructure

The resource agent for SAP HANA is included in SUSE Linux Enterprise Server for SAP Applications. An image for SUSE Linux Enterprise Server for SAP Applications 12 or 15 is available in Azure Marketplace. You can use the image to deploy new VMs.

Deploy Linux VMs manually via Azure portal

This document assumes that you've already deployed a resource group, Azure Virtual Network, and subnet.

Deploy virtual machines for SAP HANA. Choose a suitable SLES image that is supported for HANA system. You can deploy VM in any one of the availability options - virtual machine scale set, availability zone, or availability set.

Important

Make sure that the OS you select is SAP certified for SAP HANA on the specific VM types that you plan to use in your deployment. You can look up SAP HANA-certified VM types and their OS releases in SAP HANA Certified IaaS Platforms. Make sure that you look at the details of the VM type to get the complete list of SAP HANA-supported OS releases for the specific VM type.

Configure Azure load balancer

During VM configuration, you have an option to create or select exiting load balancer in networking section. Follow below steps, to setup standard load balancer for high availability setup of HANA database.

Azure Portal

Follow the steps in Create load balancer to set up a standard load balancer for a high-availability SAP system by using the Azure portal. During the setup of the load balancer, consider the following points:

1. Frontend IP Configuration: Create a front-end IP. Select the same virtual network and subnet name as your database virtual machines.
2. Backend Pool: Create a back-end pool and add database VMs.
3. Inbound rules: Create a load-balancing rule. Follow the same steps for both load-balancing rules.
   • Frontend IP address: Select a front-end IP.
   • Backend pool: Select a back-end pool.
   • High-availability ports: Select this option.
   • Protocol: Select TCP.
   • Health Probe: Create a health probe with the following details:
     • Protocol: Select TCP.
     • Port: For example, 625<instance-no.>.
     • Interval: Enter 5.
     • Probe Threshold: Enter 2.
   • Idle timeout (minutes): Enter 30.
   • Enable Floating IP: Select this option.

Note

The health probe configuration property numberOfProbes, otherwise known as Unhealthy threshold in the portal, isn't respected. To control the number of successful or failed consecutive probes, set the property probeThreshold to 2. It's currently not possible to set this property by using the Azure portal, so use either the Azure CLI or the PowerShell command.

Azure CLI

# Create the load balancer resource with frontend IP. Allocation of private IP address is dynamic using below command. If you want to pass static IP address, include parameter --private-ip-address.
az network lb create -g MyResourceGroup -n MyLB --sku Standard --vnet-name MyVMsVirtualNetwork --subnet MyVMsSubnet --backend-pool-name MyBackendPool --frontend-ip-name MyDBFrontendIpName

# Create the health probe
az network lb probe create -g MyResourceGroup --lb-name MyLB -n MyDBHealthProbe --protocol tcp --port MyDBHealthProbePort --interval 5 --probe-threshold 2
 
# Create load balancing rule
az network lb rule create -g MyResourceGroup --lb-name MyLB -n MyDBRuleName --protocol All --frontend-ip-name MyDBFrontendIpName --frontend-port 0 --backend-pool-name MyBackendPool --backend-port 0 --probe-name MyDBHealthProbe --idle-timeout-in-minutes 30 --enable-floating-ip 

# Add database VMs in backend pool
az network nic ip-config address-pool add --address-pool MyBackendPool --ip-config-name DBVm1IpConfigName --nic-name DBVm1NicName -g MyResourceGroup --lb-name MyLB
az network nic ip-config address-pool add --address-pool MyBackendPool --ip-config-name DBVm2IpConfigName --nic-name DBVm2NicName -g MyResourceGroup --lb-name MyLB

Expand to view full CLI code

# Define variables for Resource Group, and Database VMs.

rg_name="resourcegroup-name"
vm1_name="db1-name"
vm2_name="db2-name"

# Define variables for the load balancer that will be utilized in the creation of the load balancer resource.

lb_name="sap-db-sid-ilb"
bkp_name="db-backendpool"
db_fip_name="db-frontendip"

db_hp_name="db-healthprobe"
db_hp_port="625<instance-no>"

db_rule_name="db-lb-rule"
 
# Command to get VMs network information like primary NIC name, primary IP configuration name, virtual network name, and subnet name. 
 
vm1_primary_nic=$(az vm nic list -g $rg_name --vm-name $vm1_name --query "[?primary == \`true\`].{id:id} || [?primary == \`null\`].{id:id}" -o tsv)
vm1_nic_name=$(basename $vm1_primary_nic)
vm1_ipconfig=$(az network nic ip-config list -g $rg_name --nic-name $vm1_nic_name --query "[?primary == \`true\`].name" -o tsv)
 
vm2_primary_nic=$(az vm nic list -g $rg_name --vm-name $vm2_name --query "[?primary == \`true\`].{id:id} || [?primary == \`null\`].{id:id}" -o tsv)
vm2_nic_name=$(basename $vm2_primary_nic)
vm2_ipconfig=$(az network nic ip-config list -g $rg_name --nic-name $vm2_nic_name --query "[?primary == \`true\`].name" -o tsv)
 
vnet_subnet_id=$(az network nic show -g $rg_name -n $vm1_nic_name --query ipConfigurations[0].subnet.id -o tsv)
vnet_name=$(basename $(dirname $(dirname $vnet_subnet_id)))
subnet_name=$(basename $vnet_subnet_id)
 
# Create the load balancer resource with frontend IP.
# Allocation of private IP address is dynamic using below command. If you want to pass static IP address, include parameter --private-ip-address. 
  
az network lb create -g $rg_name -n $lb_name --sku Standard --vnet-name $vnet_name --subnet $subnet_name --backend-pool-name $bkp_name --frontend-ip-name $db_fip_name
 
# Create the health probe
 
az network lb probe create -g $rg_name --lb-name $lb_name -n $db_hp_name --protocol tcp --port $db_hp_port --interval 5 --probe-threshold 2
 
# Create load balancing rule
  
az network lb rule create -g $rg_name --lb-name $lb_name -n  $db_rule_name --protocol All --frontend-ip-name $db_fip_name --frontend-port 0 --backend-pool-name $bkp_name --backend-port 0 --probe-name $db_hp_name --idle-timeout-in-minutes 30 --enable-floating-ip 
 
# Add database VMs in backend pool
 
az network nic ip-config address-pool add --address-pool $bkp_name --ip-config-name $vm1_ipconfig --nic-name $vm1_nic_name -g $rg_name --lb-name $lb_name
az network nic ip-config address-pool add --address-pool $bkp_name --ip-config-name $vm2_ipconfig --nic-name $vm2_nic_name -g $rg_name --lb-name $lb_name

# [OPTIONAL] Change the assignment of frontend IP address from dynamic to static
dbfip=$(az network lb frontend-ip show --lb-name $lb_name -g $rg_name -n $db_fip_name --query "{privateIPAddress:privateIPAddress}" -o tsv)
az network lb frontend-ip update --lb-name $lb_name -g $rg_name -n $db_fip_name --private-ip-address $dbfip

PowerShell

# Create frontend IP configurations
$db_fip = New-AzLoadBalancerFrontendIpConfig -Name MyDBFrontendIpName -SubnetId MyDBSubnetName

# Create backend pool
$bePool = New-AzLoadBalancerBackendAddressPoolConfig -Name MyBackendPool

# Create health probe
$db_healthprobe = New-AzLoadBalancerProbeConfig -Name MyDBHealthProbe -Protocol 'tcp' -Port MyDBHealthProbePort -IntervalInSeconds 5 -ProbeThreshold 2 -ProbeCount 1

# Create load balancing rule
$db_rule = New-AzLoadBalancerRuleConfig -Name MyDBRuleName -Probe $db_healthprobe -Protocol 'All' -IdleTimeoutInMinutes 30 -FrontendIpConfiguration $db_fip -BackendAddressPool $bePool -EnableFloatingIP

# Create the load balancer resource
$lb = New-AzLoadBalancer -ResourceGroupName MyResourceGroup -Name MyLB -Location MyRegion -Sku 'Standard' -FrontendIpConfiguration $db_fip -BackendAddressPool $bePool -LoadBalancingRule $db_rule -Probe $db_healthprobe

Expand to view full PowerShell code

# Define variables for Resource Group, and Database VMs.

$rg_name = 'resourcegroup-name'
$vm1_name = 'db1-name'
$vm2_name = 'db2-name'

# Define variables for the load balancer that will be utilized in the creation of the load balancer resource.

$lb_name = 'sap-db-sid-ilb'
$bkp_name = 'db-backendpool'
$db_fip_name = 'db-frontendip'
 
$db_hp_name = 'db-healthprobe'
$db_hp_port = '625<instance-no>'
 
$db_rule_name = 'db-lb-rule'
 
# Command to get VMs network information like primary NIC name, primary IP configuration name, virtual network name, and subnet name.
 
$vm1 = Get-AzVM -ResourceGroupName $rg_name -Name $vm1_name
$vm1_primarynic = $vm1.NetworkProfile.NetworkInterfaces | Where-Object {($_.Primary -eq "True") -or ($_.Primary -eq $null)}
$vm1_nic_name = $vm1_primarynic.Id.Split('/')[-1]
 
$vm1_nic_info = Get-AzNetworkInterface -Name $vm1_nic_name -ResourceGroupName $rg_name
$vm1_primaryip = $vm1_nic_info.IpConfigurations | Where-Object -Property Primary -EQ -Value "True"
$vm1_ipconfig_name = ($vm1_primaryip).Name
 
$vm2 = Get-AzVM -ResourceGroupName $rg_name -Name $vm2_name
$vm2_primarynic = $vm2.NetworkProfile.NetworkInterfaces | Where-Object {($_.Primary -eq "True") -or ($_.Primary -eq $null)}
$vm2_nic_name = $vm2_primarynic.Id.Split('/')[-1]
 
$vm2_nic_info = Get-AzNetworkInterface -Name $vm2_nic_name -ResourceGroupName $rg_name
$vm2_primaryip = $vm2_nic_info.IpConfigurations | Where-Object -Property Primary -EQ -Value "True"
$vm2_ipconfig_name = ($vm2_primaryip).Name
 
$vnet_name = $vm1_primaryip.Subnet.Id.Split('/')[-3]
$subnet_name = $vm1_primaryip.Subnet.Id.Split('/')[-1]
$location = $vm1.Location
 
# Create frontend IP resource.
# Allocation of private IP address is dynamic using below command. If you want to pass static IP address, include parameter -PrivateIpAddress
 
$db_lb_fip = @{
    Name = $db_fip_name
    SubnetId = $vm1_primaryip.Subnet.Id
}
$db_fip = New-AzLoadBalancerFrontendIpConfig @db_lb_fip

# Create backend pool
 
$bepool = New-AzLoadBalancerBackendAddressPoolConfig -Name $bkp_name

# Create the health probe
 
$db_probe = @{
    Name = $db_hp_name
    Protocol = 'tcp'
    Port = $db_hp_port
    IntervalInSeconds = '5'
    ProbeThreshold = '2'
    ProbeCount = '1'
}
$db_healthprobe = New-AzLoadBalancerProbeConfig @db_probe
    
# Create load balancing rule
 
$db_lbrule = @{
    Name = $db_rule_name
    Probe = $db_healthprobe
    Protocol = 'All'
    IdleTimeoutInMinutes = '30'
    FrontendIpConfiguration = $db_fip
    BackendAddressPool = $bePool 
} 
$db_rule = New-AzLoadBalancerRuleConfig @db_lbrule -EnableFloatingIP 
 
# Create the load balancer resource
 
$loadbalancer = @{
    ResourceGroupName = $rg_name
    Name = $lb_name
    Location = $location
    Sku = 'Standard'
    FrontendIpConfiguration = $db_fip
    BackendAddressPool = $bePool
    LoadBalancingRule = $db_rule
    Probe = $db_healthprobe
} 
$lb = New-AzLoadBalancer @loadbalancer

# Add DB VMs in backend pool
 
$vm1_primaryip.LoadBalancerBackendAddressPools.Add($lb.BackendAddressPools[0])
$vm2_primaryip.LoadBalancerBackendAddressPools.Add($lb.BackendAddressPools[0])
$vm1_nic_info | Set-AzNetworkInterface
$vm2_nic_info | Set-AzNetworkInterface

For more information about the required ports for SAP HANA, read the chapter Connections to Tenant Databases in the SAP HANA Tenant Databases guide or SAP Note 2388694.

Note

When VMs that don't have public IP addresses are placed in the back-end pool of an internal (no public IP address) standard instance of Azure Load Balancer, the default configuration is no outbound internet connectivity. You can take extra steps to allow routing to public endpoints. For details on how to achieve outbound connectivity, see Public endpoint connectivity for VMs by using Azure Standard Load Balancer in SAP high-availability scenarios.

Important

• Don't enable TCP timestamps on Azure VMs that are placed behind Azure Load Balancer. Enabling TCP timestamps causes the health probes to fail. Set parameter net.ipv4.tcp_timestamps to 0. For details see Load Balancer health probes or SAP note 2382421.
• To prevent saptune from changing the manually set net.ipv4.tcp_timestamps value from 0 back to 1, update saptune version to 3.1.1 or higher. For more details, see saptune 3.1.1 – Do I Need to Update?.

Create a Pacemaker cluster

Follow the steps in Set up Pacemaker on SUSE Linux Enterprise Server in Azure to create a basic Pacemaker cluster for this HANA server. You can use the same Pacemaker cluster for SAP HANA and SAP NetWeaver (A)SCS.

Install SAP HANA

The steps in this section use the following prefixes:

• [A]: The step applies to all nodes.
• [1]: The step applies only to node 1.
• [2]: The step applies only to node 2 of the Pacemaker cluster.

Replace <placeholders> with the values for your SAP HANA installation.

1. [A] Set up the disk layout by using Logical Volume Manager (LVM).

   We recommend that you use LVM for volumes that store data and log files. The following example assumes that the VMs have four attached data disks that are used to create two volumes.

   1. Run this command to list all the available disks:

      /dev/disk/azure/scsi1/lun*
      

      Example output:

      /dev/disk/azure/scsi1/lun0  /dev/disk/azure/scsi1/lun1  /dev/disk/azure/scsi1/lun2  /dev/disk/azure/scsi1/lun3
      

   2. Create physical volumes for all the disks that you want to use:

      sudo pvcreate /dev/disk/azure/scsi1/lun0
      sudo pvcreate /dev/disk/azure/scsi1/lun1
      sudo pvcreate /dev/disk/azure/scsi1/lun2
      sudo pvcreate /dev/disk/azure/scsi1/lun3
      

   3. Create a volume group for the data files. Use one volume group for the log files and one volume group for the shared directory of SAP HANA:

      sudo vgcreate vg_hana_data_<HANA SID> /dev/disk/azure/scsi1/lun0 /dev/disk/azure/scsi1/lun1
      sudo vgcreate vg_hana_log_<HANA SID> /dev/disk/azure/scsi1/lun2
      sudo vgcreate vg_hana_shared_<HANA SID> /dev/disk/azure/scsi1/lun3
      

   4. Create the logical volumes.

      A linear volume is created when you use lvcreate without the -i switch. We suggest that you create a striped volume for better I/O performance. Align the stripe sizes to the values that are described in SAP HANA VM storage configurations. The -i argument should be the number of underlying physical volumes, and the -I argument is the stripe size.

      For example, if two physical volumes are used for the data volume, the -i switch argument is set to 2, and the stripe size for the data volume is 256KiB. One physical volume is used for the log volume, so no -i or -I switches are explicitly used for the log volume commands.

      Important

      When you use more than one physical volume for each data volume, log volume, or shared volume, use the -i switch and set it the number of underlying physical volumes. When you create a striped volume, use the -I switch to specify the stripe size.

      For recommended storage configurations, including stripe sizes and the number of disks, see SAP HANA VM storage configurations.

      sudo lvcreate <-i number of physical volumes> <-I stripe size for the data volume> -l 100%FREE -n hana_data vg_hana_data_<HANA SID>
      sudo lvcreate -l 100%FREE -n hana_log vg_hana_log_<HANA SID>
      sudo lvcreate -l 100%FREE -n hana_shared vg_hana_shared_<HANA SID>
      sudo mkfs.xfs /dev/vg_hana_data_<HANA SID>/hana_data
      sudo mkfs.xfs /dev/vg_hana_log_<HANA SID>/hana_log
      sudo mkfs.xfs /dev/vg_hana_shared_<HANA SID>/hana_shared
      

   5. Create the mount directories and copy the universally unique identifier (UUID) of all the logical volumes:

      sudo mkdir -p /hana/data/<HANA SID>
      sudo mkdir -p /hana/log/<HANA SID>
      sudo mkdir -p /hana/shared/<HANA SID>
      # Write down the ID of /dev/vg_hana_data_<HANA SID>/hana_data, /dev/vg_hana_log_<HANA SID>/hana_log, and /dev/vg_hana_shared_<HANA SID>/hana_shared
      sudo blkid
      

   6. Edit the /etc/fstab file to create fstab entries for the three logical volumes:

      sudo vi /etc/fstab
      

   7. Insert the following lines in the /etc/fstab file:

      /dev/disk/by-uuid/<UUID of /dev/mapper/vg_hana_data_<HANA SID>-hana_data> /hana/data/<HANA SID> xfs  defaults,nofail  0  2
      /dev/disk/by-uuid/<UUID of /dev/mapper/vg_hana_log_<HANA SID>-hana_log> /hana/log/<HANA SID> xfs  defaults,nofail  0  2
      /dev/disk/by-uuid/<UUID of /dev/mapper/vg_hana_shared_<HANA SID>-hana_shared> /hana/shared/<HANA SID> xfs  defaults,nofail  0  2
      

   8. Mount the new volumes:

      sudo mount -a
      

2. [A] Set up the disk layout by using plain disks.

   For demo systems, you can place your HANA data and log files on one disk.

   1. Create a partition on /dev/disk/azure/scsi1/lun0 and format it by using XFS:

      sudo sh -c 'echo -e "n\n\n\n\n\nw\n" | fdisk /dev/disk/azure/scsi1/lun0'
      sudo mkfs.xfs /dev/disk/azure/scsi1/lun0-part1
      
      # Write down the ID of /dev/disk/azure/scsi1/lun0-part1
      sudo /sbin/blkid
      sudo vi /etc/fstab
      

   2. Insert this line in the /etc/fstab file:

      /dev/disk/by-uuid/<UUID> /hana xfs  defaults,nofail  0  2
      

   3. Create the target directory and mount the disk:

      sudo mkdir /hana
      sudo mount -a
      

3. [A] Set up host name resolution for all hosts.

   You can either use a DNS server or modify the /etc/hosts file on all nodes. This example shows you how to use the /etc/hosts file. Replace the IP addresses and the host names in the following commands.

   1. Edit the /etc/hosts file:

      sudo vi /etc/hosts
      

   2. Insert the following lines in the /etc/hosts file. Change the IP addresses and host names to match your environment.

      10.0.0.5 hn1-db-0
      10.0.0.6 hn1-db-1
      

4. [A] Install SAP HANA, following SAP's documentation.

Configure SAP HANA 2.0 system replication

The steps in this section use the following prefixes:

• [A]: The step applies to all nodes.
• [1]: The step applies only to node 1.
• [2]: The step applies only to node 2 of the Pacemaker cluster.

Replace <placeholders> with the values for your SAP HANA installation.

1. [1] Create the tenant database.

   If you're using SAP HANA 2.0 or SAP HANA MDC, create a tenant database for your SAP NetWeaver system.

   Run the following command as <HANA SID>adm:

   hdbsql -u SYSTEM -p "<password>" -i <instance number> -d SYSTEMDB 'CREATE DATABASE <SAP SID> SYSTEM USER PASSWORD "<password>"'
   

2. [1] Configure system replication on the first node:

   First, back up the databases as <HANA SID>adm:

   hdbsql -d SYSTEMDB -u SYSTEM -p "<password>" -i <instance number> "BACKUP DATA USING FILE ('<name of initial backup file for SYS>')"
   hdbsql -d <HANA SID> -u SYSTEM -p "<password>" -i <instance number> "BACKUP DATA USING FILE ('<name of initial backup file for HANA SID>')"
   hdbsql -d <SAP SID> -u SYSTEM -p "<password>" -i <instance number> "BACKUP DATA USING FILE ('<name of initial backup file for SAP SID>')"
   

   Then, copy the system public key infrastructure (PKI) files to the secondary site:

   scp /usr/sap/<HANA SID>/SYS/global/security/rsecssfs/data/SSFS_<HANA SID>.DAT   hn1-db-1:/usr/sap/<HANA SID>/SYS/global/security/rsecssfs/data/
   scp /usr/sap/<HANA SID>/SYS/global/security/rsecssfs/key/SSFS_<HANA SID>.KEY  hn1-db-1:/usr/sap/<HANA SID>/SYS/global/security/rsecssfs/key/
   

   Create the primary site:

   hdbnsutil -sr_enable --name=<site 1>
   

3. [2] Configure system replication on the second node:

   Register the second node to start the system replication.

   Run the following command as <HANA SID>adm:

   sapcontrol -nr <instance number> -function StopWait 600 10
   hdbnsutil -sr_register --remoteHost=hn1-db-0 --remoteInstance=<instance number> --replicationMode=sync --name=<site 2> 
   

Implement HANA resource agents

SUSE provides two different software packages for the Pacemaker resource agent to manage SAP HANA. Software packages SAPHanaSR and SAPHanaSR-angi are using slightly different syntax and parameters and aren't compatible. See SUSE release notes and documentation for details and differences between SAPHanaSR and SAPHanaSR-angi. This document covers both packages in separate tabs in the respective sections.

Warning

Don't replace the package SAPHanaSR by SAPHanaSR-angi in an already configured cluster. Upgrading from SAPHanaSR to SAPHanaSR-angi requires a specific procedure.

1. [A] Install the SAP HANA high availability packages:

SAPHanaSR

Run the following command to install the high availability packages:

sudo zypper install SAPHanaSR

SAPHanaSR-angi

Important

SAPHanaSR-angi has a minimum version requirement of SAP HANA 2.0 SPS 05 and SUSE SLES for SAP Applications 15 SP4 or higher.

Run the following command to install the high availability packages:

sudo zypper install SAPHanaSR-angi

Set up SAP HANA HA/DR providers

The SAP HANA HA/DR providers optimize the integration with the cluster and improve detection when a cluster failover is needed. The main hook script is SAPHanaSR (for SAPHanaSR package) / susHanaSR (for SAPHanaSR-angi). We highly recommend that you configure the SAPHanaSR/susHanaSR Python hook. For HANA 2.0 SPS 05 and later, we recommend that you implement both SAPHanaSR/susHanaSR and the susChkSrv hooks.

The susChkSrv hook extends the functionality of the main SAPHanaSR/susHanaSR HA provider. It acts when the HANA process hdbindexserver crashes. If a single process crashes, HANA typically tries to restart it. Restarting the indexserver process can take a long time, during which the HANA database isn't responsive.

With susChkSrv implemented, an immediate and configurable action is executed. The action triggers a failover in the configured timeout period instead of waiting for the hdbindexserver process to restart on the same node.

1. [A] Stop HANA on both nodes.

Run the following code as <sap-sid>adm:

sapcontrol -nr <instance number> -function StopSystem

2. [A] Install the HANA system replication hooks. The hooks must be installed on both HANA database nodes.

   Tip

   The SAPHanaSR Python hook can be implemented only for HANA 2.0. The SAPHanaSR package must be at least version 0.153.
   The SAPHanaSR-angi Python hook can be implemented only for HANA 2.0 SPS 05 and later.
   The susChkSrv Python hook requires SAP HANA 2.0 SPS 05, and SAPHanaSR version 0.161.1_BF or later must be installed.

   SAPHanaSR

   1. [A] Adjust global.ini on each cluster node.

      If the requirements for the susChkSrv hook aren't met, remove the entire [ha_dr_provider_suschksrv] block from the following parameters. You can adjust the behavior of susChkSrv by using the action_on_lost parameter. Valid values are [ ignore | stop | kill | fence ].

      [ha_dr_provider_SAPHanaSR]
      provider = SAPHanaSR
      path = /usr/share/SAPHanaSR
      execution_order = 1
      
      [ha_dr_provider_suschksrv]
      provider = susChkSrv
      path = /usr/share/SAPHanaSR
      execution_order = 3
      action_on_lost = fence
      
      [trace]
      ha_dr_saphanasr = info
      

      If you point parameter path to the default /usr/share/SAPHanaSR location, the Python hook code updates automatically through OS updates or package updates. HANA uses the hook code updates when it next restarts. With an optional own path like /hana/shared/myHooks, you can decouple OS updates from the hook version that you use.

   2. [A] The cluster requires sudoers configuration on each cluster node for <sap-sid>adm. In this example, that's achieved by creating a new file.

      Run the following command as root. Replace <sid> by lowercase SAP system ID, <SID> by uppercase SAP system ID and <siteA/B> with HANA site names chosen.

      cat << EOF > /etc/sudoers.d/20-saphana
      # Needed for SAPHanaSR and susChkSrv Python hooks
      Cmnd_Alias SOK_SITEA      = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteA> -v SOK   -t crm_config -s SAPHanaSR
      Cmnd_Alias SFAIL_SITEA    = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteA> -v SFAIL -t crm_config -s SAPHanaSR
      Cmnd_Alias SOK_SITEB      = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteB> -v SOK   -t crm_config -s SAPHanaSR
      Cmnd_Alias SFAIL_SITEB    = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteB> -v SFAIL -t crm_config -s SAPHanaSR
      Cmnd_Alias HELPER_TAKEOVER = /usr/sbin/SAPHanaSR-hookHelper --sid=<SID> --case=checkTakeover
      Cmnd_Alias HELPER_FENCE    = /usr/sbin/SAPHanaSR-hookHelper --sid=<SID> --case=fenceMe
      
      <sid>adm ALL=(ALL) NOPASSWD: SOK_SITEA, SFAIL_SITEA, SOK_SITEB, SFAIL_SITEB, HELPER_TAKEOVER, HELPER_FENCE
      EOF
      

   For details about implementing the SAP HANA system replication hook, see Set up HANA HA/DR providers.

   SAPHanaSR-angi

   1. [A] Adjust global.ini on each cluster node.

      If you choose not to use the recommended susChkSrv hook, remove the entire [ha_dr_provider_suschksrv] block from the following parameters. You can adjust the behavior of susChkSrv by using the action_on_lost parameter. Valid values are [ ignore | stop | kill | fence ].

      [ha_dr_provider_sushanasr]
      provider = susHanaSR
      path = /usr/share/SAPHanaSR-angi
      execution_order = 1
      
      [ha_dr_provider_suschksrv]
      provider = susChkSrv
      path = /usr/share/SAPHanaSR-angi
      execution_order = 3
      action_on_lost = fence
      
      [trace]
      ha_dr_sushanasr = info
      ha_dr_saphanasr = info
      

      If you point parameter path to the default /usr/share/SAPHanaSR-angi location, the Python hook code updates automatically through OS updates or package updates. HANA uses the hook code updates when it next restarts. With an optional own path like /hana/shared/myHooks, you can decouple OS updates from the hook version that you use.

   2. [A] The cluster requires sudoers configuration on each cluster node for <sap-sid>adm. In this example, that's achieved by creating a new file.

      Run the following command as root. Replace <sid> by lowercase SAP system ID, <SID> by uppercase SAP system ID and <siteA/B> with HANA site names chosen.

      cat << EOF > /etc/sudoers.d/20-saphana
      # Needed for susHanaSR and susChkSrv Python hooks
      Cmnd_Alias SOK_SITEA    = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteA> -v SOK   -t crm_config -s SAPHanaSR
      Cmnd_Alias SFAIL_SITEA  = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteA> -v SFAIL -t crm_config -s SAPHanaSR
      Cmnd_Alias SOK_SITEB    = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteB> -v SOK   -t crm_config -s SAPHanaSR
      Cmnd_Alias SFAIL_SITEB  = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteB> -v SFAIL -t crm_config -s SAPHanaSR
      Cmnd_Alias HELPER_TAKEOVER  = /usr/bin/SAPHanaSR-hookHelper --sid=<SID> --case=checkTakeover
      Cmnd_Alias HELPER_FENCE     = /usr/bin/SAPHanaSR-hookHelper --sid=<SID> --case=fenceMe
      
      <sid>adm ALL=(ALL) NOPASSWD: SOK_SITEA, SFAIL_SITEA, SOK_SITEB, SFAIL_SITEB, HELPER_TAKEOVER, HELPER_FENCE
      EOF
      

      For details about implementing the SAP HANA system replication hook, see Set up HANA HA/DR providers.

---

3. [A] Start SAP HANA on both nodes. Run the following command as <sap-sid>adm:

   sapcontrol -nr <instance number> -function StartSystem 
   

4. [1] Verify the hook installation. Run the following command as <sap-sid>adm on the active HANA system replication site:

   SAPHanaSR

   cdtrace
   awk '/ha_dr_SAPHanaSR.*crm_attribute/ \
   { printf "%s %s %s %s\n",$2,$3,$5,$16 }' nameserver_*
   # Example output
   # 2021-04-08 22:18:15.877583 ha_dr_SAPHanaSR SFAIL
   # 2021-04-08 22:18:46.531564 ha_dr_SAPHanaSR SFAIL
   # 2021-04-08 22:21:26.816573 ha_dr_SAPHanaSR SOK
   

   SAPHanaSR-angi

   cdtrace
   grep HADR.*load.*SAPHanaSR nameserver_*.trc
   # Example output
   # ha_dr_provider HADRProviderManager.cpp(00083) : loading HA/DR Provider 'susHanaSR' from /usr/share/SAPHanaSR-angi
   

---

5. [1] Verify the susChkSrv hook installation. Run the following command as <sap-sid>adm on HANA VMs:

   cdtrace
   egrep '(LOST:|STOP:|START:|DOWN:|init|load|fail)' nameserver_suschksrv.trc
   # Example output
   # 2022-11-03 18:06:21.116728  susChkSrv.init() version 0.7.7, parameter info: action_on_lost=fence stop_timeout=20 kill_signal=9
   # 2022-11-03 18:06:27.613588  START: indexserver event looks like graceful tenant start
   # 2022-11-03 18:07:56.143766  START: indexserver event looks like graceful tenant start (indexserver started)
   

Create SAP HANA cluster resources

1. [1] First, create the HANA topology resource.

SAPHanaSR

Run the following commands on one of the Pacemaker cluster nodes:

sudo crm configure property maintenance-mode=true

# Replace <placeholders> with your instance number and HANA system ID

sudo crm configure primitive rsc_SAPHanaTopology_<HANA SID>_HDB<instance number> ocf:suse:SAPHanaTopology \
  operations \$id="rsc_sap2_<HANA SID>_HDB<instance number>-operations" \
  op monitor interval="10" timeout="600" \
  op start interval="0" timeout="600" \
  op stop interval="0" timeout="300" \
  params SID="<HANA SID>" InstanceNumber="<instance number>"

sudo crm configure clone cln_SAPHanaTopology_<HANA SID>_HDB<instance number> rsc_SAPHanaTopology_<HANA SID>_HDB<instance number> \
  meta clone-node-max="1" target-role="Started" interleave="true"

SAPHanaSR-angi

Run the following commands on one of the Pacemaker cluster nodes:

sudo crm configure property maintenance-mode=true

# Replace <placeholders> with your instance number and HANA system ID

sudo crm configure primitive rsc_SAPHanaTopology_<HANA SID>_HDB<instance number> ocf:suse:SAPHanaTopology \
  op monitor interval="50" timeout="600" \
  op start interval="0" timeout="600" \
  op stop interval="0" timeout="300" \
  params SID="<HANA SID>" InstanceNumber="<instance number>"

sudo crm configure clone cln_SAPHanaTopology_<HANA SID>_HDB<instance number> rsc_SAPHanaTopology_<HANA SID>_HDB<instance number> \
  meta clone-node-max="1" interleave="true"

2. [1] Next, create the HANA resources:

SAPHanaSR

Note

This article contains references to terms that Microsoft no longer uses. When these terms are removed from the software, we'll remove them from this article.

# Replace <placeholders> with your instance number and HANA system ID.

sudo crm configure primitive rsc_SAPHana_<HANA SID>_HDB<instance number> ocf:suse:SAPHana \
  operations \$id="rsc_sap_<HANA SID>_HDB<instance number>-operations" \
  op start interval="0" timeout="3600" \
  op stop interval="0" timeout="3600" \
  op promote interval="0" timeout="3600" \
  op monitor interval="60" role="Master" timeout="700" \
  op monitor interval="61" role="Slave" timeout="700" \
  params SID="<HANA SID>" InstanceNumber="<instance number>" PREFER_SITE_TAKEOVER="true" \
  DUPLICATE_PRIMARY_TIMEOUT="7200" AUTOMATED_REGISTER="false"

# Run the following command if the cluster nodes are running on SLES 12 SP05.
sudo crm configure ms msl_SAPHana_<HANA SID>_HDB<instance number> rsc_SAPHana_<HANA SID>_HDB<instance number> \
  meta notify="true" clone-max="2" clone-node-max="1" \
  target-role="Started" interleave="true"

# Run the following command if the cluster nodes are running on SLES 15 SP03 or later.
sudo crm configure clone msl_SAPHana_<HANA SID>_HDB<instance number> rsc_SAPHana_<HANA SID>_HDB<instance number> \
  meta notify="true" clone-max="2" clone-node-max="1" \
  target-role="Started" interleave="true" promotable="true"

sudo crm resource meta msl_SAPHana_<HANA SID>_HDB<instance number> set priority 100

SAPHanaSR-angi

# Replace <placeholders> with your instance number and HANA system ID. 
sudo crm configure primitive rsc_SAPHanaCon_<HANA SID>_HDB<instance number> ocf:suse:SAPHanaController \
  op start interval="0" timeout="3600" \
  op stop  interval="0" timeout="3600" \
  op promote interval="0" timeout="3600" \
  op demote  interval="0" timeout="320"  \
  op monitor interval="60" role="Promoted" timeout="700" \
  op monitor interval="61" role="Unpromoted" timeout="700" \
  params SID="<HANA SID>" InstanceNumber="<instance number>" PREFER_SITE_TAKEOVER="true" \
  DUPLICATE_PRIMARY_TIMEOUT="7200" AUTOMATED_REGISTER="false" \
  meta priority=100

sudo crm configure clone mst_SAPHanaCon_<HANA SID>_HDB<instance number> rsc_SAPHanaCon_<HANA SID>_HDB<instance number> \
  meta clone-node-max="1" interleave="true" promotable="true"

SAPHanaSR-angi adds a new resource agent SAPHanaFilesystem to monitor read/write access to /hana/shared/SID. OS static mounts the /hana/shared/SID filesystem with each host having entries in /etc/fstab. SAPHanaFilesystem and Pacemaker doesn't mount the filesystem for HANA.

We recommend implementing SAPHanaFilesystem if using NFS for /hana/shared/SID location. When /hana/shared/SID is located on a block device, such as Azure managed disk, the use of SAPHanaFilesystem is optional.

# Replace <placeholders> with your instance number and HANA system ID. 
sudo crm configure primitive rsc_SAPHanaFil_<HANA SID>_HDB<instance number> ocf:suse:SAPHanaFilesystem \
  op start interval="0" timeout="10" \
  op stop interval="0" timeout="20" \
  op monitor interval="120" timeout="120" \
  params SID="<HANA SID>" InstanceNumber="<instance number>" ON_FAIL_ACTION="fence"

sudo crm configure clone cln_SAPHanaFil_<HANA SID>_HDB<instance number> rsc_SAPHanaFil_<HANA SID>_HDB<instance number> \
  meta clone-node-max="1" interleave="true"

3. [1] Continue with cluster resources for virtual IPs, defaults, and constraints.

SAPHanaSR

# Replace <placeholders> with your instance number, HANA system ID, and the front-end IP address of the Azure load balancer. 
sudo crm configure primitive rsc_ip_<HANA SID>_HDB<instance number> ocf:heartbeat:IPaddr2 \
  meta target-role="Started" \
  operations \$id="rsc_ip_<HANA SID>_HDB<instance number>-operations" \
  op monitor interval="10s" timeout="20s" \
  params ip="<front-end IP address>"

sudo crm configure primitive rsc_nc_<HANA SID>_HDB<instance number> azure-lb port=625<instance number> \
  op monitor timeout=20s interval=10 \
  meta resource-stickiness=0

sudo crm configure group g_ip_<HANA SID>_HDB<instance number> rsc_ip_<HANA SID>_HDB<instance number> rsc_nc_<HANA SID>_HDB<instance number>

sudo crm configure colocation col_saphana_ip_<HANA SID>_HDB<instance number> 4000: g_ip_<HANA SID>_HDB<instance number>:Started \
  msl_SAPHana_<HANA SID>_HDB<instance number>:Master  

sudo crm configure order ord_SAPHana_<HANA SID>_HDB<instance number> Optional: cln_SAPHanaTopology_<HANA SID>_HDB<instance number> \
  msl_SAPHana_<HANA SID>_HDB<instance number>

# Clean up the HANA resources. The HANA resources might have failed because of a known issue.
sudo crm resource cleanup rsc_SAPHana_<HANA SID>_HDB<instance number>

sudo crm configure property priority-fencing-delay=30

sudo crm configure property maintenance-mode=false
sudo crm configure rsc_defaults resource-stickiness=1000
sudo crm configure rsc_defaults migration-threshold=5000

SAPHanaSR-angi

# Replace <placeholders> with your instance number, HANA system ID, and the front-end IP address of the Azure load balancer. 
sudo crm configure primitive rsc_ip_<HANA SID>_HDB<instance number> ocf:heartbeat:IPaddr2 \
  meta target-role="Started" \
  op monitor interval="10s" timeout="20s" \
  params ip="<front-end IP address>"

sudo crm configure primitive rsc_nc_<HANA SID>_HDB<instance number> azure-lb port=625<instance number> \
  op monitor timeout=20s interval=10 \
  meta resource-stickiness=0

sudo crm configure group g_ip_<HANA SID>_HDB<instance number> rsc_ip_<HANA SID>_HDB<instance number> rsc_nc_<HANA SID>_HDB<instance number>

sudo crm configure colocation col_saphana_ip_<HANA SID>_HDB<instance number> 4000: g_ip_<HANA SID>_HDB<instance number>:Started \
  mst_SAPHanaCon_<HANA SID>_HDB<instance number>:Promoted  

sudo crm configure order ord_SAPHana_<HANA SID>_HDB<instance number> Optional: cln_SAPHanaTopology_<HANA SID>_HDB<instance number> \
  mst_SAPHanaCon_<HANA SID>_HDB<instance number>

# Clean up the HANA resources. The HANA resources might have failed because of a known issue.
sudo crm resource cleanup rsc_SAPHanaCon_<HANA SID>_HDB<instance number>

sudo crm configure property priority-fencing-delay=30

sudo crm configure property maintenance-mode=false
sudo crm configure rsc_defaults resource-stickiness=1000
sudo crm configure rsc_defaults migration-threshold=5000

Important

We recommend that you set AUTOMATED_REGISTER to false only while you complete thorough failover tests, to prevent a failed primary instance from automatically registering as secondary. When the failover tests are successfully completed, set AUTOMATED_REGISTER to true, so that after takeover, system replication automatically resumes.

Make sure that the cluster status is OK and that all the resources started. It doesn't matter which node the resources are running on.

sudo crm_mon -r

# Online: [ hn1-db-0 hn1-db-1 ]
#
# Full list of resources:
#
# stonith-sbd     (stonith:external/sbd): Started hn1-db-0
# Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
#     Started: [ hn1-db-0 hn1-db-1 ]
# Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
#     Masters: [ hn1-db-0 ]
#     Slaves: [ hn1-db-1 ]
# Resource Group: g_ip_HN1_HDB03
#     rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
#     rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0

Configure HANA active/read-enabled system replication in a Pacemaker cluster

In SAP HANA 2.0 SPS 01 and later versions, SAP allows an active/read-enabled setup for SAP HANA system replication. In this scenario, the secondary systems of SAP HANA system replication can be actively used for read-intensive workloads.

To support this setup in a cluster, a second virtual IP address is required so that clients can access the secondary read-enabled SAP HANA database. To ensure that the secondary replication site can still be accessed after a takeover, the cluster needs to move the virtual IP address around with the secondary of the SAPHana resource.

This section describes the extra steps that are required to manage a HANA active/read-enabled system replication in a SUSE high availability cluster that uses a second virtual IP address.

Before you proceed, make sure that you have fully configured the SUSE high availability cluster that manages SAP HANA database as described in earlier sections.

Set up the load balancer for active/read-enabled system replication

To proceed with extra steps to provision the second virtual IP, make sure that you configured Azure Load Balancer as described in Deploy Linux VMs manually via Azure portal.

For the standard load balancer, complete these extra steps on the same load balancer that you created earlier.

1. Create a second front-end IP pool:
   1. Open the load balancer, select frontend IP pool, and select Add.
   2. Enter the name of the second front-end IP pool (for example, hana-secondaryIP).
   3. Set the Assignment to Static and enter the IP address (for example, 10.0.0.14).
   4. Select OK.
   5. After the new front-end IP pool is created, note the front-end IP address.
2. Create a health probe:
   1. In the load balancer, select health probes, and select Add.
   2. Enter the name of the new health probe (for example, hana-secondaryhp).
   3. Select TCP as the protocol and port 626<instance number>. Keep the Interval value set to 5, and the Unhealthy threshold value set to 2.
   4. Select OK.
3. Create the load-balancing rules:
   1. In the load balancer, select load balancing rules, and select Add.
   2. Enter the name of the new load balancer rule (for example, hana-secondarylb).
   3. Select the front-end IP address, the back-end pool, and the health probe that you created earlier (for example, hana-secondaryIP, hana-backend, and hana-secondaryhp).
   4. Select HA Ports.
   5. Increase idle timeout to 30 minutes.
   6. Make sure that you enable floating IP.
   7. Select OK.

Set up HANA active/read-enabled system replication

The steps to configure HANA system replication are described in Configure SAP HANA 2.0 system replication. If you're deploying a read-enabled secondary scenario, when you set up system replication on the second node, run the following command as <HANA SID>adm:

sapcontrol -nr <instance number> -function StopWait 600 10 

hdbnsutil -sr_register --remoteHost=hn1-db-0 --remoteInstance=<instance number> --replicationMode=sync --name=<site 2> --operationMode=logreplay_readaccess 

Add a secondary virtual IP address resource

You can set up the second virtual IP and the appropriate colocation constraint by using the following commands:

SAPHanaSR

crm configure property maintenance-mode=true

crm configure primitive rsc_secip_<HANA SID>_HDB<instance number> ocf:heartbeat:IPaddr2 \
 meta target-role="Started" \
 operations \$id="rsc_secip_<HANA SID>_HDB<instance number>-operations" \
 op monitor interval="10s" timeout="20s" \
 params ip="<secondary IP address>"

crm configure primitive rsc_secnc_<HANA SID>_HDB<instance number> azure-lb port=626<instance number> \
 op monitor timeout=20s interval=10 \
 meta resource-stickiness=0

crm configure group g_secip_<HANA SID>_HDB<instance number> rsc_secip_<HANA SID>_HDB<instance number> rsc_secnc_<HANA SID>_HDB<instance number>

crm configure colocation col_saphana_secip_<HANA SID>_HDB<instance number> 4000: g_secip_<HANA SID>_HDB<instance number>:Started \
 msl_SAPHana_<HANA SID>_HDB<instance number>:Slave 

crm configure property maintenance-mode=false

SAPHanaSR-angi

crm configure property maintenance-mode=true

crm configure primitive rsc_secip_<HANA SID>_HDB<instance number> ocf:heartbeat:IPaddr2 \
 op monitor interval="10s" timeout="20s" \
 params ip="<secondary IP address>"

crm configure primitive rsc_secnc_<HANA SID>_HDB<instance number> azure-lb port=626<instance number> \
 op monitor timeout=20s interval=10 \
 meta resource-stickiness=0

crm configure group g_secip_<HANA SID>_HDB<instance number> rsc_secip_<HANA SID>_HDB<instance number> rsc_secnc_<HANA SID>_HDB<instance number>

crm configure colocation col_saphana_secip_<HANA SID>_HDB<instance number> 4000: g_secip_<HANA SID>_HDB<instance number>:Started \
 mst_SAPHanaCon_<HANA SID>_HDB<instance number>:Unpromoted 

crm configure property maintenance-mode=false

Make sure that the cluster status is OK and that all the resources started. The second virtual IP runs on the secondary site along with the SAPHana secondary resource.

sudo crm_mon -r

# Online: [ hn1-db-0 hn1-db-1 ]
#
# Full list of resources:
#
# stonith-sbd     (stonith:external/sbd): Started hn1-db-0
# Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
#     Started: [ hn1-db-0 hn1-db-1 ]
# Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
#     Masters: [ hn1-db-0 ]
#     Slaves: [ hn1-db-1 ]
# Resource Group: g_ip_HN1_HDB03
#     rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
#     rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
# Resource Group: g_secip_HN1_HDB03:
#     rsc_secip_HN1_HDB03       (ocf::heartbeat:IPaddr2):        Started hn1-db-1
#     rsc_secnc_HN1_HDB03       (ocf::heartbeat:azure-lb):       Started hn1-db-1

The next section describes the typical set of failover tests to execute.

Considerations when you test a HANA cluster that's configured with a read-enabled secondary:

• When you migrate the SAPHana_<HANA SID>_HDB<instance number> cluster resource to hn1-db-1, the second virtual IP moves to hn1-db-0. If you have configured AUTOMATED_REGISTER="false" and HANA system replication isn't registered automatically, the second virtual IP runs on hn1-db-0 because the server is available and cluster services are online.

• When you test a server crash, the second virtual IP resources (rsc_secip_<HANA SID>_HDB<instance number>) and the Azure load balancer port resource (rsc_secnc_<HANA SID>_HDB<instance number>) run on the primary server alongside the primary virtual IP resources. While the secondary server is down, the applications that are connected to a read-enabled HANA database connect to the primary HANA database. The behavior is expected because you don't want applications that are connected to a read-enabled HANA database to be inaccessible while the secondary server is unavailable.

• When the secondary server is available and the cluster services are online, the second virtual IP and port resources automatically move to the secondary server, even though HANA system replication might not be registered as secondary. Make sure that you register the secondary HANA database as read-enabled before you start cluster services on that server. You can configure the HANA instance cluster resource to automatically register the secondary by setting the parameter AUTOMATED_REGISTER="true".

• During failover and fallback, the existing connections for applications, which are then using the second virtual IP to connect to the HANA database, might be interrupted.

Test the cluster setup

This section describes how you can test your setup. Every test assumes that you're signed in as root and that the SAP HANA master is running on the hn1-db-0 VM.

Test the migration

Before you start the test, make sure that Pacemaker doesn't have any failed action (run crm_mon -r), that there are no unexpected location constraints (for example, leftovers of a migration test), and that HANA is in sync state, for example, by running SAPHanaSR-showAttr.

SAPHanaSR

hn1-db-0:~ # SAPHanaSR-showAttr
Sites    srHook
----------------
SITE2    SOK
Global cib-time
--------------------------------
global Mon Aug 13 11:26:04 2018
Hosts    clone_state lpa_hn1_lpt node_state op_mode   remoteHost    roles                            score site  srmode sync_state version                vhost
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
hn1-db-0 PROMOTED    1534159564  online     logreplay nws-hana-vm-1 4:P:master1:master:worker:master 150   SITE1 sync   PRIM       2.00.030.00.1522209842 nws-hana-vm-0
hn1-db-1 DEMOTED     30          online     logreplay nws-hana-vm-0 4:S:master1:master:worker:master 100   SITE2 sync   SOK        2.00.030.00.1522209842 nws-hana-vm-1

SAPHanaSR-angi

hn1-db-0:~ # SAPHanaSR-showAttr
Global cib-update dcid prim      sec sid topology
--------------------------------------------------
global 0.130728.2 1    SITE1 -   HN1 ScaleUp

Resource                      promotable
-----------------------------------------
mst_SAPHanaCon_HN1_HDB03      true
cln_SAPHanaTopology_HN1_HDB03

Site        lpt        lss mns      opMode    srHook srMode srPoll srr
-----------------------------------------------------------------------
SITE1       1722604101 4   hn1-db-0 logreplay PRIM   sync   PRIM   P
SITE2       30         4   hn1-db-1 logreplay SWAIT  sync   SOK    S

Host     clone_state roles                        score site    sra srah version     vhost
---------------------------------------------------------------------------------------------
hn1-db-0 PROMOTED    master1:master:worker:master 150   SITE1   -   -    2.00.074.00 hn1-db-0
hn1-db-1 DEMOTED     master1:master:worker:master 100   SITE2       -    2.00.074.00 hn1-db-1

Host     clone_state roles                        score site      sra srah version     vhost
------------------------------------------------------------------------------------------------
hn1-db-0 PROMOTED    master1:master:worker:master 150   SITE1     -   -    2.00.074.00 hn1-db-0
hn1-db-1                                                SITE2                          hn1-db-1

You can migrate the SAP HANA master node by running the following command:

crm resource move msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-1 force

The cluster would migrate the SAP HANA master node and the group containing virtual IP address to hn1-db-1.

When the migration is finished, the crm_mon -r output looks like this example:

Online: [ hn1-db-0 hn1-db-1 ]

Full list of resources:
stonith-sbd     (stonith:external/sbd): Started hn1-db-1
 Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
     Started: [ hn1-db-0 hn1-db-1 ]
 Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
     Masters: [ hn1-db-1 ]
     Stopped: [ hn1-db-0 ]
 Resource Group: g_ip_HN1_HDB03
     rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
     rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1
Failed Actions:
* rsc_SAPHana_HN1_HDB03_start_0 on hn1-db-0 'not running' (7): call=84, status=complete, exitreason='none',
    last-rc-change='Mon Aug 13 11:31:37 2018', queued=0ms, exec=2095ms

With AUTOMATED_REGISTER="false", the cluster wouldn't restart the failed HANA database or register it against the new primary on hn1-db-0. In this case, configure the HANA instance as secondary by running this command:

su - <hana sid>adm

# Stop the HANA instance, just in case it is running
hn1adm@hn1-db-0:/usr/sap/HN1/HDB03> sapcontrol -nr <instance number> -function StopWait 600 10
hn1adm@hn1-db-0:/usr/sap/HN1/HDB03> hdbnsutil -sr_register --remoteHost=hn1-db-1 --remoteInstance=<instance number> --replicationMode=sync --name=<site 1>

The migration creates location constraints that need to be deleted again:

# Switch back to root and clean up the failed state
exit
hn1-db-0:~ # crm resource clear msl_SAPHana_<HANA SID>_HDB<instance number>

You also need to clean up the state of the secondary node resource:

hn1-db-0:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-0

Monitor the state of the HANA resource by using crm_mon -r. When HANA is started on hn1-db-0, the output looks like this example:

Online: [ hn1-db-0 hn1-db-1 ]

Full list of resources:
stonith-sbd     (stonith:external/sbd): Started hn1-db-1
 Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
     Started: [ hn1-db-0 hn1-db-1 ]
 Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
     Masters: [ hn1-db-1 ]
     Slaves: [ hn1-db-0 ]
 Resource Group: g_ip_HN1_HDB03
     rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
     rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1

Blocking network communication

Resource state before starting the test:

Online: [ hn1-db-0 hn1-db-1 ]

Full list of resources:
stonith-sbd     (stonith:external/sbd): Started hn1-db-1
 Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
     Started: [ hn1-db-0 hn1-db-1 ]
 Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
     Masters: [ hn1-db-1 ]
     Slaves: [ hn1-db-0 ]
 Resource Group: g_ip_HN1_HDB03
     rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
     rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1

Execute firewall rule to block the communication on one of the nodes.

# Execute iptable rule on hn1-db-1 (10.0.0.6) to block the incoming and outgoing traffic to hn1-db-0 (10.0.0.5)
iptables -A INPUT -s 10.0.0.5 -j DROP; iptables -A OUTPUT -d 10.0.0.5 -j DROP

When cluster nodes can't communicate to each other, there's a risk of a split-brain scenario. In such situations, cluster nodes will try to simultaneously fence each other, resulting in fence race.

When configuring a fencing device, it's recommended to configure pcmk_delay_max property. So, in the event of split-brain scenario, the cluster introduces a random delay up to the pcmk_delay_max value, to the fencing action on each node. The node with the shortest delay will be selected for fencing.

Additionally, to ensure that the node running the HANA master takes priority and wins the fence race in a split brain scenario, it's recommended to set priority-fencing-delay property in the cluster configuration. By enabling priority-fencing-delay property, the cluster can introduce an additional delay in the fencing action specifically on the node hosting HANA master resource, allowing the node to win the fence race.

Execute below command to delete the firewall rule.

# If the iptables rule set on the server gets reset after a reboot, the rules will be cleared out. In case they have not been reset, please proceed to remove the iptables rule using the following command.
iptables -D INPUT -s 10.0.0.5 -j DROP; iptables -D OUTPUT -d 10.0.0.5 -j DROP

Test SBD fencing

You can test the setup of SBD by killing the inquisitor process:

hn1-db-0:~ # ps aux | grep sbd
root       1912  0.0  0.0  85420 11740 ?        SL   12:25   0:00 sbd: inquisitor
root       1929  0.0  0.0  85456 11776 ?        SL   12:25   0:00 sbd: watcher: /dev/disk/by-id/scsi-360014056f268462316e4681b704a9f73 - slot: 0 - uuid: 7b862dba-e7f7-4800-92ed-f76a4e3978c8
root       1930  0.0  0.0  85456 11776 ?        SL   12:25   0:00 sbd: watcher: /dev/disk/by-id/scsi-360014059bc9ea4e4bac4b18808299aaf - slot: 0 - uuid: 5813ee04-b75c-482e-805e-3b1e22ba16cd
root       1931  0.0  0.0  85456 11776 ?        SL   12:25   0:00 sbd: watcher: /dev/disk/by-id/scsi-36001405b8dddd44eb3647908def6621c - slot: 0 - uuid: 986ed8f8-947d-4396-8aec-b933b75e904c
root       1932  0.0  0.0  90524 16656 ?        SL   12:25   0:00 sbd: watcher: Pacemaker
root       1933  0.0  0.0 102708 28260 ?        SL   12:25   0:00 sbd: watcher: Cluster
root      13877  0.0  0.0   9292  1572 pts/0    S+   12:27   0:00 grep sbd

hn1-db-0:~ # kill -9 1912

The <HANA SID>-db-<database 1> cluster node reboots. The Pacemaker service might not restart. Make sure that you start it again.

Test a manual failover

You can test a manual failover by stopping the Pacemaker service on the hn1-db-0 node:

service pacemaker stop

After the failover, you can start the service again. If you set AUTOMATED_REGISTER="false", the SAP HANA resource on the hn1-db-0 node fails to start as secondary.

In this case, configure the HANA instance as secondary by running this command:

service pacemaker start
su - <hana sid>adm

# Stop the HANA instance, just in case it is running
sapcontrol -nr <instance number> -function StopWait 600 10
hdbnsutil -sr_register --remoteHost=hn1-db-1 --remoteInstance=<instance number> --replicationMode=sync --name=<site 1> 

# Switch back to root and clean up the failed state
exit
crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-0

SUSE tests

Important

Make sure that the OS that you select is SAP certified for SAP HANA on the specific VM types you plan to use. You can look up SAP HANA-certified VM types and their OS releases in SAP HANA Certified IaaS Platforms. Make sure that you look at the details of the VM type you plan to use to get the complete list of SAP HANA-supported OS releases for that VM type.

Run all test cases that are listed in the SAP HANA SR Performance Optimized Scenario guide or SAP HANA SR Cost Optimized Scenario guide, depending on your scenario. You can find the guides listed in SLES for SAP best practices.

The following tests are a copy of the test descriptions of the SAP HANA SR Performance Optimized Scenario SUSE Linux Enterprise Server for SAP Applications 12 SP1 guide. For an up-to-date version, also read the guide itself. Always make sure that HANA is in sync before you start the test, and make sure that the Pacemaker configuration is correct.

In the following test descriptions, we assume PREFER_SITE_TAKEOVER="true" and AUTOMATED_REGISTER="false".

Note

The following tests are designed to be run in sequence. Each test depends on the exit state of the preceding test.

1. Test 1: Stop the primary database on node 1.

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

   Run the following commands as <hana sid>adm on the hn1-db-0 node:

   hn1adm@hn1-db-0:/usr/sap/HN1/HDB03> HDB stop
   

   Pacemaker detects the stopped HANA instance and fails over to the other node. When the failover is finished, the HANA instance on the hn1-db-0 node is stopped because Pacemaker doesn't automatically register the node as HANA secondary.

   Run the following commands to register the hn1-db-0 node as secondary and clean up the failed resource:

   hn1adm@hn1-db-0:/usr/sap/HN1/HDB03> hdbnsutil -sr_register --remoteHost=hn1-db-1 --remoteInstance=<instance number> --replicationMode=sync --name=<site 1>
   
   # run as root
   hn1-db-0:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-0
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-1 ]
      Slaves: [ hn1-db-0 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1
   

2. Test 2: Stop the primary database on node 2.

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-1 ]
      Slaves: [ hn1-db-0 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1
   

   Run the following commands as <hana sid>adm on the hn1-db-1 node:

   hn1adm@hn1-db-1:/usr/sap/HN1/HDB01> HDB stop
   

   Pacemaker detects the stopped HANA instance and fails over to the other node. When the failover is finished, the HANA instance on the hn1-db-1 node is stopped because Pacemaker doesn't automatically register the node as HANA secondary.

   Run the following commands to register the hn1-db-1 node as secondary and clean up the failed resource:

   hn1adm@hn1-db-1:/usr/sap/HN1/HDB03> hdbnsutil -sr_register --remoteHost=hn1-db-0 --remoteInstance=<instance number> --replicationMode=sync --name=<site 2>
   
   # run as root
   hn1-db-1:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-1
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

3. Test 3: Crash the primary database on node 1.

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

   Run the following commands as <hana sid>adm on the hn1-db-0 node:

   hn1adm@hn1-db-0:/usr/sap/HN1/HDB03> HDB kill-9
   

   Pacemaker detects the killed HANA instance and fails over to the other node. When the failover is finished, the HANA instance on the hn1-db-0 node is stopped because Pacemaker doesn't automatically register the node as HANA secondary.

   Run the following commands to register the hn1-db-0 node as secondary and clean up the failed resource:

   hn1adm@hn1-db-0:/usr/sap/HN1/HDB03> hdbnsutil -sr_register --remoteHost=hn1-db-1 --remoteInstance=<instance number> --replicationMode=sync --name=<site 1>
   
   # run as root
   hn1-db-0:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-0
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-1 ]
      Slaves: [ hn1-db-0 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1
   

4. Test 4: Crash the primary database on node 2.

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-1 ]
      Slaves: [ hn1-db-0 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1
   

   Run the following commands as <hana sid>adm on the hn1-db-1 node:

   hn1adm@hn1-db-1:/usr/sap/HN1/HDB03> HDB kill-9
   

   Pacemaker detects the killed HANA instance and fails over to the other node. When the failover is finished, the HANA instance on the hn1-db-1 node is stopped because Pacemaker doesn't automatically register the node as HANA secondary.

   Run the following commands to register the hn1-db-1 node as secondary and clean up the failed resource.

   hn1adm@hn1-db-1:/usr/sap/HN1/HDB03> hdbnsutil -sr_register --remoteHost=hn1-db-0 --remoteInstance=<instance number> --replicationMode=sync --name=<site 2>
   
   # run as root
   hn1-db-1:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-1
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

5. Test 5: Crash the primary site node (node 1).

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

   Run the following commands as root on the hn1-db-0 node:

   hn1-db-0:~ #  echo 'b' > /proc/sysrq-trigger
   

   Pacemaker detects the killed cluster node and fences the node. When the node is fenced, Pacemaker triggers a takeover of the HANA instance. When the fenced node is rebooted, Pacemaker doesn't start automatically.

   Run the following commands to start Pacemaker, clean the SBD messages for the hn1-db-0 node, register the hn1-db-0 node as secondary, and clean up the failed resource:

   # run as root
   # list the SBD device(s)
   hn1-db-0:~ # cat /etc/sysconfig/sbd | grep SBD_DEVICE=
   # SBD_DEVICE="/dev/disk/by-id/scsi-36001405772fe8401e6240c985857e116;/dev/disk/by-id/scsi-36001405034a84428af24ddd8c3a3e9e1;/dev/disk/by-id/scsi-36001405cdd5ac8d40e548449318510c3"
   
   hn1-db-0:~ # sbd -d /dev/disk/by-id/scsi-36001405772fe8401e6240c985857e116 -d /dev/disk/by-id/scsi-36001405034a84428af24ddd8c3a3e9e1 -d /dev/disk/by-id/scsi-36001405cdd5ac8d40e548449318510c3 message hn1-db-0 clear
   
   hn1-db-0:~ # systemctl start pacemaker
   
   # run as <hana sid>adm
   hn1adm@hn1-db-0:/usr/sap/HN1/HDB03> hdbnsutil -sr_register --remoteHost=hn1-db-1 --remoteInstance=<instance number> --replicationMode=sync --name=<site 1>
   
   # run as root
   hn1-db-0:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-0
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-1 ]
      Slaves: [ hn1-db-0 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1
   

6. Test 6: Crash the secondary site node (node 2).

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-1 ]
      Slaves: [ hn1-db-0 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1
   

   Run the following commands as root on the hn1-db-1 node:

   hn1-db-1:~ #  echo 'b' > /proc/sysrq-trigger
   

   Pacemaker detects the killed cluster node and fences the node. When the node is fenced, Pacemaker triggers a takeover of the HANA instance. When the fenced node is rebooted, Pacemaker doesn't start automatically.

   Run the following commands to start Pacemaker, clean the SBD messages for the hn1-db-1 node, register the hn1-db-1 node as secondary, and clean up the failed resource:

   # run as root
   # list the SBD device(s)
   hn1-db-1:~ # cat /etc/sysconfig/sbd | grep SBD_DEVICE=
   # SBD_DEVICE="/dev/disk/by-id/scsi-36001405772fe8401e6240c985857e116;/dev/disk/by-id/scsi-36001405034a84428af24ddd8c3a3e9e1;/dev/disk/by-id/scsi-36001405cdd5ac8d40e548449318510c3"
   
   hn1-db-1:~ # sbd -d /dev/disk/by-id/scsi-36001405772fe8401e6240c985857e116 -d /dev/disk/by-id/scsi-36001405034a84428af24ddd8c3a3e9e1 -d /dev/disk/by-id/scsi-36001405cdd5ac8d40e548449318510c3 message hn1-db-1 clear
   
   hn1-db-1:~ # systemctl start pacemaker
   
   # run as <hana sid>adm
   hn1adm@hn1-db-1:/usr/sap/HN1/HDB03> hdbnsutil -sr_register --remoteHost=hn1-db-0 --remoteInstance=<instance number> --replicationMode=sync --name=<site 2>
   
   # run as root
   hn1-db-1:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-1
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   </code></pre>
   

7. Test 7: Stop the secondary database on node 2.

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

   Run the following commands as <hana sid>adm on the hn1-db-1 node:

   hn1adm@hn1-db-1:/usr/sap/HN1/HDB03> HDB stop
   

   Pacemaker detects the stopped HANA instance and marks the resource as failed on the hn1-db-1 node. Pacemaker automatically restarts the HANA instance.

   Run the following command to clean up the failed state:

   # run as root
   hn1-db-1>:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-1
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

8. Test 8: Crash the secondary database on node 2.

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

   Run the following commands as <hana sid>adm on the hn1-db-1 node:

   hn1adm@hn1-db-1:/usr/sap/HN1/HDB03> HDB kill-9
   

   Pacemaker detects the killed HANA instance and marks the resource as failed on the hn1-db-1 node. Run the following command to clean up the failed state. Pacemaker then automatically restarts the HANA instance.

   # run as root
   hn1-db-1:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> HN1-db-1
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

9. Test 9: Crash the secondary site node (node 2) that's running the secondary HANA database.

   The resource state before starting the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

   Run the following commands as root on the hn1-db-1 node:

   hn1-db-1:~ # echo b > /proc/sysrq-trigger
   

   Pacemaker detects the killed cluster node and fenced the node. When the fenced node is rebooted, Pacemaker doesn't start automatically.

   Run the following commands to start Pacemaker, clean the SBD messages for the hn1-db-1 node, and clean up the failed resource:

   # run as root
   # list the SBD device(s)
   hn1-db-1:~ # cat /etc/sysconfig/sbd | grep SBD_DEVICE=
   # SBD_DEVICE="/dev/disk/by-id/scsi-36001405772fe8401e6240c985857e116;/dev/disk/by-id/scsi-36001405034a84428af24ddd8c3a3e9e1;/dev/disk/by-id/scsi-36001405cdd5ac8d40e548449318510c3"
   
   hn1-db-1:~ # sbd -d /dev/disk/by-id/scsi-36001405772fe8401e6240c985857e116 -d /dev/disk/by-id/scsi-36001405034a84428af24ddd8c3a3e9e1 -d /dev/disk/by-id/scsi-36001405cdd5ac8d40e548449318510c3 message hn1-db-1 clear
   
   hn1-db-1:~ # systemctl start pacemaker  
   
   hn1-db-1:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-1
   

   The resource state after the test:

   Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
      Started: [ hn1-db-0 hn1-db-1 ]
   Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
      Masters: [ hn1-db-0 ]
      Slaves: [ hn1-db-1 ]
   Resource Group: g_ip_HN1_HDB03
      rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
      rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
   

10. Test 10: Crash primary database indexserver

    This test is relevant only when you have set up the susChkSrv hook as outlined in Implement HANA resource agents.

    The resource state before starting the test:

    Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
       Started: [ hn1-db-0 hn1-db-1 ]
    Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
       Masters: [ hn1-db-0 ]
       Slaves: [ hn1-db-1 ]
    Resource Group: g_ip_HN1_HDB03
       rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-0
       rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-0
    

    Run the following commands as root on the hn1-db-0 node:

    hn1-db-0:~ # killall -9 hdbindexserver
    

    When the indexserver is terminated, the susChkSrv hook detects the event and triggers an action to fence 'hn1-db-0' node and initiate a takeover process.

    Run the following commands to register hn1-db-0 node as secondary and clean up the failed resource:

    # run as <hana sid>adm
    hn1adm@hn1-db-0:/usr/sap/HN1/HDB03> hdbnsutil -sr_register --remoteHost=hn1-db-1 --remoteInstance=<instance number> --replicationMode=sync --name=<site 1>
    
    # run as root
    hn1-db-0:~ # crm resource cleanup msl_SAPHana_<HANA SID>_HDB<instance number> hn1-db-0
    

    The resource state after the test:

    Clone Set: cln_SAPHanaTopology_HN1_HDB03 [rsc_SAPHanaTopology_HN1_HDB03]
       Started: [ hn1-db-0 hn1-db-1 ]
    Master/Slave Set: msl_SAPHana_HN1_HDB03 [rsc_SAPHana_HN1_HDB03]
       Masters: [ hn1-db-1 ]
       Slaves: [ hn1-db-0 ]
    Resource Group: g_ip_HN1_HDB03
       rsc_ip_HN1_HDB03   (ocf::heartbeat:IPaddr2):       Started hn1-db-1
       rsc_nc_HN1_HDB03   (ocf::heartbeat:azure-lb):      Started hn1-db-1
    

    You can execute a comparable test case by causing the indexserver on the secondary node to crash. In the event of indexserver crash, the susChkSrv hook recognizes the occurrence and initiate an action to fence the secondary node.

Next steps

• Azure Virtual Machines planning and implementation for SAP
• Azure Virtual Machines deployment for SAP
• Azure Virtual Machines DBMS deployment for SAP