Run SAP HANA for Linux virtual machines in a scale-up architecture on Azure

This reference architecture shows a set of proven practices for running SAP HANA in a highly available, scale-up environment that supports disaster recovery on Azure. This implementation focuses on the database layer only.

Architecture

This reference architecture describes a common production system. You can choose the virtual machine sizes to accommodate your organization's needs. This configuration can also be reduced to one virtual machine, depending on business requirements.

The following diagram shows a reference architecture for SAP HANA on Azure:

Download a Visio file that contains the diagrams in this article.

Workflow

This reference architecture describes a typical SAP HANA database running in Azure, in a highly available deployment to maximize system availability. The architecture and its components can be customized based on business requirements (RTO, RPO, uptime expectations, system role) and potentially reduced to a single VM. The network layout is simplified to demonstrate the architectural principals of such SAP environment and not intended to describe a full enterprise network.

Networking

Virtual networks. The Azure Virtual Network service connects Azure resources to each other with enhanced security. In this architecture, the virtual network connects to an on-premises environment via an ExpressRoute gateway deployed in the hub of a hub-spoke topology. SAP HANA database is contained in own spoke virtual network. The spoke virtual networks contains one subnet for the database virtual machines (VMs).

If applications connecting to SAP HANA are running on VMs, the application VMs should be located in same virtual network but within a dedicated application subnet. Alternatively, if SAP HANA connection isn't the primary database, the application VMs can be located in other virtual networks. Separating into subnets by workload allows easier enablement of network security groups (NSG) to set security rules applicable to SAP HANA VMs only.

Zone-redundant gateway. A gateway connects distinct networks, extending your on-premises network to the Azure virtual network. We recommend that you use ExpressRoute to create private connections that don't go over the public internet, but you can also use a site-to-site connection. Use zone-redundant Azure ExpressRoute or VPN gateways to guard against zone failures. See Zone-redundant virtual network gateways to understand the differences between a zonal deployment and a zone-redundant deployment. It's worth mentioning here that the IP addresses used need to be of Standard SKU for a zone deployment of the gateways.

Network security groups (NSG). To restrict incoming and outgoing network traffic of the virtual network, create network security groups, which are in turn assigned to specific subnets. DB and application subnets are secured with workload specific NSGs.

Application security groups (ASG). To define fine-grained network security policies inside your NSGs based on workloads that are centered on applications, use application security groups instead of explicit IP addresses. They let you group network interfaces of VMs by name and help you secure applications by filtering traffic from trusted segments of your network.

Network interface cards (NICs). Network interface cards enable all communication among virtual machines on a virtual network. Traditional on-premises SAP deployments implement multiple NICs per machine to segregate administrative traffic from business traffic.

On Azure, it's not necessary to use multiple NICs for performance reasons. Multiple NICs share the same network throughput limit of a VM. But if your organization needs to segregate traffic, you can deploy multiple NICs per VM and connect each NIC to a different subnet. You can then use network security groups to enforce different access control policies on each subnet.

Azure NICs support multiple IPs. This support conforms with the SAP recommended practice of using virtual host names for installations. For a complete outline, see SAP note 962955. (To access SAP notes, you need an SAP Service Marketplace account.)

Virtual machines

This architecture uses virtual machines (VM). Azure offers single-node scale up to 23.5 Tebibytes (TiB) of memory on virtual machines. The SAP Certified and Supported SAP HANA Hardware Directory lists the virtual machines that are certified for the SAP HANA database. For details about SAP support for virtual machine types and throughput metrics (SAPS), see SAP Note 1928533 - SAP Applications on Microsoft Azure: Supported Products and Azure VM types. (To access this and other SAP notes, an SAP Service Marketplace account is required.)

Microsoft and SAP jointly certify a range of virtual machine sizes for SAP HANA workloads. For example, smaller deployments can run on an Edsv4 or Edsv5 virtual machine with 160 GiB or more of RAM. To support the largest SAP HANA memory sizes on virtual machines, as much as 30 TiB, you can use Mv3-series virtual machines.

Generation 2 (Gen2) virtual machines. When you deploy VMs, you can use either generation 1 or generation 2 VMs. Generation 2 VMs support key features that aren't available for generation 1 VMs. For SAP HANA, this is particularly important because some VM families, like Mv2 and Mdsv2, are supported only as Gen2 VMs. Similarly, SAP on Azure certification for some newer VMs might require them to be only Gen2 for full support, even if Azure allows both on them. See details in SAP Note 1928533 - SAP Applications on Microsoft Azure: Supported Products and Azure VM types.

Because all other VMs supporting SAP HANA allow the choice of either Gen2 only or Gen1+2 selectively, we recommend that you deploy all SAP VMs as Gen2 only. This applies also to VMs with low memory requirements. Even the smallest SAP HANA VM can run as Gen2 VM and can be, when deallocated, be resized to the largest VM available in your region.

Proximity Placement Groups (PPG). When virtual machines are deployed in availability zones, latency within the zone is usually ideal for almost all SAP HANA uses. To optimize network latency further, you can use proximity placement groups. This means that virtual machines are in the same datacenter to minimize latency between SAP HANA and connecting application VMs. For SAP HANA architecture itself, no PPGs are needed, they're only an option collocating SAP HANA with application tier VMs. Due to potential restrictions with PPGs, adding the database AvSet to the SAP system's PPG should be done sparsely and only when required for latency between SAP application and database traffic. For more information on the usage scenarios of PPGs, see the linked documentation. As PPGs restrict workloads to a single datacenter, a PPG can't span multiple availability zones.

Components

• Azure Virtual Network
• Azure ExpressRoute
• Azure Virtual Machines
• Azure NetApp Files
• Azure Load Balancer
• Azure Disk Storage

Considerations

This section describes key considerations for running SAP HANA on Azure.

Scalability

This architecture runs SAP HANA on virtual machines that can scale up to 30 TiB in one instance.

If your workload exceeds the maximum virtual machine size, we recommend that you use multi-node HANA configurations. For online transaction processing (OLTP) applications, total scale-out memory capacity can be as high as 4 x 30 TiB. For online analytical processing (OLAP) applications, the scale-out memory capacity can be as high as 16 x 15.2 TiB. For example, you can deploy SAP HANA in a scale-out configuration with standby on virtual machines—running either Red Hat Enterprise Linux or SUSE Linux Enterprise Server—using Azure NetApp Files for the shared storage volumes.

Storage

This architecture uses Azure managed disks for storage on the virtual machines or Azure NetApp Files. Guidelines for storage deployment with managed disks are in detail within the SAP HANA Azure virtual machine storage configurations document. Alternatively to managed disks, Azure NetApp Files NFS volumes can be used as storage solution for SAP HANA.

To achieve high input/output operations per second (IOPS) and disk storage throughput, the common practices in storage volume performance optimization also apply to Azure storage layout. For example, combining multiple disks together with LVM to create a striped disk volume improves IO performance. Azure disk caching also plays a significant role in achieving required IO performance.

For SAP HANA log disks that run on Azure Premium SSD v1, use one of the following technologies in locations that hold /hana/log for production:

• Write Accelerator (on M series VMs)
• Ultra disks (on either M or E series VMs)
• Azure NetApp Files (on either M or E series VMs)

These technologies are needed to consistently meet the required storage latency of less than 1 ms.

Azure Premium SSD v2 is designed for performance-critical workloads like SAP. Write Accelerator isn't required when /hana/log is running on Premium SSD v2. For information about this storage solution's benefits and current limitations, see Deploy a Premium SSD v2.

For details about SAP HANA performance requirements, see SAP Note 1943937 - Hardware Configuration Check Tool.

• Cost-conscious storage design for non-production systems. For SAP HANA environments that don't require maximum storage performance in all situations, you can use a storage architecture that's optimized for cost. This choice of storage optimization can apply to little-used production systems or some non-production SAP HANA environments. The cost-optimized storage option uses a combination of Standard SSDs instead of the Premium or Ultra SSDs that are used for production environments. It also combines /hana/data and /hana/log file systems onto a single set of disks. Guidelines and best practices are available for most VM sizes. If you use Azure NetApp Files for SAP HANA, you can use size-reduced volumes to achieve the same goal.

• Resizing storage when scaling-up. When you resize a virtual machine because of changed business demands or because of a growing database size, the storage configuration can change. Azure supports online disk expansion, without any interruption to service. With a striped disk setup, as used for SAP HANA, a resize operation should be done equally to all disks in the volume group. The addition of more disks to a volume group can potentially unbalance the striped data. If you're adding more disks to a storage configuration, it's far preferable to create a new storage volume on new disks. Next, copy the contents during downtime and modify mountpoints. Finally, discard the old volume group and underlying disks.

• Azure NetApp Files application volume group. For deployments with SAP HANA files contained on Azure NetApp Files NFS volumes, application volume groups enable you to deploy all volumes according to best practices. This process also ensures optimal performance for your SAP HANA database. Details are available about how to proceed with this process. It requires manual intervention. Allow some time for the creation.

High availability

The preceding architecture depicts a highly available deployment, with SAP HANA contained on two or more virtual machines. The following components are used.

Load balancers. Azure Load Balancer is used to distribute traffic to SAP HANA virtual machines. When you incorporate Azure Load Balancer in a zonal deployment of SAP, make sure you select the Standard SKU load balancer. The Basic SKU balancer doesn't support zonal redundancy and deprecated. In this architecture, Load Balancer acts as the virtual IP address for SAP HANA. Network traffic is sent to the active VM with primary database instance. SAP HANA active/read-enabled architecture is optionally available (SLES/RHEL) where a second virtual IP addressed on the load balancer is used to direct network traffic to the secondary SAP HANA instance on another VM for read-intense workloads.

The Standard Load Balancer provides a layer of security by default. Virtual machines that are behind the Standard Load Balancer don't have outbound internet connectivity. To enable outbound internet in these virtual machines, you need to update your Standard Load Balancer configuration. In addition, you can also use an Azure NAT Gateway to get outbound connectivity.

For SAP HANA database clusters, you must enable Direct Server Return (DSR), also known as floating IP. This feature allows the server to respond with the IP address of the load balancer front end.

Deployment options. On Azure, SAP workload deployment can be either regional or zonal, depending on the availability and resiliency requirements of the SAP applications. Azure provides different deployment options, like Virtual Machine Scale Sets with Flexible orchestration (FD=1), availability zones, and availability sets, to enhance the availability of resources. To get a comprehensive understanding of the available deployment options and their applicability across different Azure regions (including across zones, within a single zone, or in a region without zones), see High-availability architecture and scenarios for SAP NetWeaver.

SAP HANA. For high availability, SAP HANA runs on two or more Linux virtual machines. SAP HANA System Replication (HSR) is used to replicate data between the primary and secondary (replica) SAP HANA systems. HSR is also used for cross-region or cross-zone disaster recovery. Depending on latency in the communication between your virtual machines, synchronous replication can be used within a region. HSR between regions for disaster recovery will in most cases be running in asynchronous manner.

For the Linux Pacemaker cluster, you need to decide which cluster fencing mechanism to use. Cluster fencing is the process of isolating a failed VM from the cluster and restarting it. For RedHat Enterprise Linux (RHEL), the only supported fencing mechanism for Pacemaker on Azure is Azure fence agent. For SUSE Linux Enterprise Server (SLES), you can use either Azure fence agent or STONITH Block Device (SBD). Compare the failover times for each solution and, if there's a difference, choose a solution based on your business requirements for recovery time objective (RTO).

Azure fence agent. This fencing method relies on the Azure ARM API, with Pacemaker querying ARM API about the status of both SAP HANA VMs in the cluster. Should one VM fail, for example OS unresponsive or VM crash, the cluster manager uses again the ARM API to restart the VM and if needed fails the SAP HANA database to the other, active node. For this purpose, a service name principal (SPN) with a custom role to query and restart VMs is used to authorize against the ARM API. No other infrastructure is needed, the SBD VMs in the architecture drawings aren't deployed in case Azure fence agent is used.

SBD. STONITH block device (SBD) uses a disk that is accessed as block device (raw, without filesystem) by the cluster manager. This disk, or disks if multiple, acts as a vote. Each of the two cluster nodes running SAP HANA accesses the SDB disks and reads/writes periodically to them small bits of information about status. Thus each cluster node knows the status about the other without depending only on networking between the VMs.

Preferably three small VMs are deployed in either an availability set or availability zone setup. Each VM exporting small parts of a disk as a block device which is accessed by the two SAP HANA cluster nodes. Three SBD VMs ensure sufficient voting members are available in case of planned or unplanned downtime for either SBD VM.

Alternatively to using SBD VMs, Azure shared disk can be used instead. The SAP HANA cluster nodes then access the single shared disk. The shared disk can be locally (LRS) or zonally (ZRS) redundant, if ZRS is available in your Azure region.

Disaster recovery

The following architecture shows a production HANA environment on Azure that provides disaster recovery. The architecture incorporates availability zones.

For DR strategies and implementation details, see Disaster recovery overview and infrastructure guidelines for SAP workload and Disaster recovery guidelines for SAP application.

In addition to a local, two-node high availability implementation, HSR supports multitier and multitarget replication. HSR therefore supports inter-zone and inter-region replication. Multitarget replication is available for SAP HANA 2.0 SPS 03 and later.

Make sure to verify your target region's resource capacity.

Azure NetApp Files. As an option, Azure NetApp Files can be used to provide a scalable and high-performance storage solution for SAP HANA data and log files. Azure NetApp Files supports snapshots for fast backup, recovery, and local replication. For cross-region content replication, Azure NetApp Files Cross-Region Replication can be used to replicate the snapshot data between two regions. Details about cross-region replication and a whitepaper describing all aspects for disaster recovery with Azure NetApp Files are available.

Backup

SAP HANA data can be backed up in many ways. After migrating to Azure, you can continue to use any existing partner backup solutions you already have. Azure provides two native approaches: SAP HANA file-level backup and Azure Backup for SAP HANA over the Backint interface.

For SAP HANA file-level backup, you can use your tool of choice, such as hdbsql or SAP HANA Studio, and store the backup files on a local disk volume. A common mount point for this backup volume is /hana/backup. Your backup policies will define the data retention period on the volume. As soon as the backup is taken, a scheduled task should copy the backup files to Azure Blob storage for safekeeping. The local backup files are kept for expedient recovery.

Azure Backup offers a simple, enterprise-grade solution for workloads running on virtual machines. Azure Backup for SAP HANA provides full integration with the SAP HANA backup catalog and guarantees database-consistent, full, or point-in-time recoveries. Azure Backup is BackInt-certified by SAP. See also the Azure Backup FAQ and support matrix.

Azure NetApp Files brings support for snapshot based backups. Integrating with SAP HANA for application consistent snapshots is through the Azure Application Consistent Snapshot tool (AzAcSnap). The snapshots created can be used for restore to a new volume for system restore or copying the SAP HANA database. Snapshots created can be used for disaster recovery, where it acts as restore point with SAP HANA logs saved on a different NFS volume.

Monitoring

To monitor your workloads on Azure, Azure Monitor lets you comprehensively collect, analyze, and act on telemetry from your cloud and on-premises environments.

For SAP applications that run on SAP HANA and other major database solutions, see Azure Monitor for SAP solutions to learn how Azure Monitor for SAP can help you manage the availability and performance of SAP services.

Security

Many security measures are used to protect the confidentiality, integrity, and availability of an SAP landscape. To secure user access, for example, SAP has its own User Management Engine (UME) to control role-based access and authorization within the SAP application and databases. For more information, see SAP HANA Security—An Overview.

For data at rest, different encryption functionalities provide security as follows:

• Along with the SAP HANA native encryption technology, consider using an encryption solution from a partner that supports customer-managed keys.

• To encrypt virtual machine disks, you can use functionalities described in Disk Encryption Overview.

• SAP Database servers: Use Transparent Data Encryption offered by the DBMS provider (for example, SAP HANA native encryption technology) to help secure your data and log files and to ensure the backups are also encrypted.

• Data in Azure physical storage (Server-Side Encryption) is automatically encrypted at rest with an Azure managed key. You can also choose a customer managed key (CMK) instead of the Azure managed key.

• For information about support of Azure Disk Encryption on particular Linux distros, versions, and images, see Azure Disk Encryption for Linux VMs.

For network security, use network security groups (NSGs) and Azure Firewall or a network virtual appliance as follows:

• Use NSGs to protect and control traffic between subnets and application/database layers. Only apply NSGs to subnets. NSGs applied to both NIC and subnet very often lead to problems during troubleshooting and should be used rarely if ever.

• Use Azure Firewall or Azure network virtual appliance to inspect and control the routing of traffic from the hub virtual network to the spoke virtual network where your SAP applications are, and also to control your outbound internet connectivity.

For User and Authorization, implement role-based access control (RBAC) and resource locks as follows:

• Follow the principle of least privilege, using RBAC for assigning administrative privileges at IaaS-level resources that host your SAP solution on Azure. The fundamental purpose of RBAC is the segregation and control of duties for your users/group. RBAC is designed to grant only the amount of access to resources that's needed to enable users to do their jobs.

• Use resource locks to help prevent accidental or malicious changes. Resource locks help prevent administrators from deleting or modifying critical Azure resources where your SAP solution is located.

More security recommendations can be found at theses Microsoft and SAP articles.

Communities

Communities can answer questions and help you set up a successful deployment. Consider the following communities:

• Azure Community Support

• SAP Community

• SAP on Stack Overflow

Contributors

This article is maintained by Microsoft. It was originally written by the following contributors.

Principal author:

• Robert Biro | Senior Architect

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Next steps

Learn more about the component technologies:

• What is Azure ExpressRoute?
• What is Azure Bastion?
• What is Power BI?
• Use the SAP Business Warehouse connector in Power BI Desktop
• SAP workload configurations with Azure Availability Zones
• What is the Azure Backup service?
• About Site Recovery
• What is Azure Load Balancer?
• Connect to SAP HANA databases in Power BI
• What is Azure NetApp Files
• Introduction to Azure managed disks
• Linux virtual machines in Azure
• Installation of SAP HANA on Azure virtual machines
• What is Azure Virtual Network?
• Network security groups
• SAP HANA Disaster Recovery with Azure NetApp Files

Related resources

Explore related architectures:

• Run a Linux VM on Azure
• Run SAP BW/4HANA with Linux virtual machines on Azure
• SAP S/4HANA in Linux on Azure
• SAP on Azure Architecture Guide