Consistency Point Objective and Azure Site Recovery

Question

Would someone be able to explain to me the difference between a "Replication policy" and a "Replication Group" when setting up Azure Site Recovery. I can't seem to find the language below anywhere in the vault other than when you first setup replication for a pair of machines. Can Replication Groups for the purpose of maintaining a Consistency Point Objective (CPO) across multiple machines be setup or modified anywhere other than here during initial setup?

Answer 1

Hello @AdamTyler-3590 Thank you for contacting through Microsoft Q&A community platform. Happy to assist!

From the details you provided, I understand that you want to know "the difference between a "replication policy" and a "replication group" when setting up azure site recovery.

A replication policy is a set of rules that define how replication should be performed for a group of virtual machines. It includes settings such as the frequency of replication, the retention period for recovery points, and the number of recovery points to keep. You can create and manage replication policies in the Azure Site Recovery vault. Reference doc link - https://learn.microsoft.com/en-us/azure/site-recovery/azure-to-azure-how-to-enable-replication

A replication group is a collection of virtual machines that are replicated together and have shared crash-consistent and app-consistent recovery points at failover. Multi-VM consistency impacts workload performance and should only be used for VMs running workloads that need consistency across all machines. You can create and manage replication groups in the Azure portal. Refer to the doc here - https://learn.microsoft.com/en-us/azure/site-recovery/azure-to-azure-common-questions#multi-vm-consistency

When you set up replication for a pair of machines, you are prompted to create a replication policy and a replication group. The replication policy defines the replication settings for the virtual machines, while the replication group defines the consistency point objective (CPO) for the group of virtual machines.

Once you have set up replication for a pair of machines, you can modify the replication policy and replication group settings in the Azure portal. To modify the replication policy, go to the Replication Policies tab in the Azure Site Recovery vault. To modify the replication group, go to the Replication Groups tab in the Azure portal.

I hope this helps! Let us know if you have any other questions.

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Answer 2

Hello @AdamTyler-3590 Thank you for contacting through Microsoft Q&A community platform.

A replication policy is a set of default settings that are applied to all the virtual machines (VMs) that are being replicated to a target region. These settings include the recovery point retention period and the app-consistent snapshot frequency. You can modify the settings of the default replication policy as you enable replication or create a new replication policy at any time and apply it when you enable replication. On the other hand, a replication group is a collection of VMs that are replicated together and have shared crash-consistent and app-consistent recovery points at failover. Multi-VM consistency impacts workload performance and should only be used for VMs running workloads that need consistency across all machines. You can create a replication group when you enable replication for a VM or add a VM to an existing replication group. You can modify the replication group settings, such as the Consistency Point Objective (CPO), after you create the replication group. To modify the CPO, you can use the Azure Portal or Azure PowerShell. However, please note that modifying the CPO can impact the workload performance and should be done with caution. If you have any further questions, please let me know.