RecoverPoint for Virtual Machines 5.3.3.2 Scale and Performance Guide

What is a CG?

A consistency group (CG) is a logical entity that defines a collection of virtual machines and their disks that are to be replicated together in a way that ensures write-order consistency.

How many CGs can a single RecoverPoint for Virtual Machines system replicate?

A single RecoverPoint for Virtual Machines system can replicate up to 512 CGs.

What affects the performance of a CG?

A CG runs on a single vRPA and the maximum performance (IOPS and throughput) of that vRPA limits that CG.

When several CGs run on the same vRPA, they share the resources of that vRPA. Higher-priority CGs consume more resources than lower-priority CGs.

For copies, the replica copy journal configuration affects the replication performance of a CG. For best practices in configuring these journals, see Choosing a datastore for journals.

How are CGs balanced over vRPAs?

When a new CG is created during VM protection, this new CG is assigned to one of the vRPAs in the vRPA cluster in a way that balances the protected capacity per vRPA. Typically, not all vRPAs have the same I/O load. Hence, you should manually modify the assignment of CGs to vRPAs to balance the I/O load. For additional information, see the RecoverPoint for Virtual Machines HTML5 Plugin Administrator’s Guide or RecoverPoint for Virtual Machines Flex Plugin Administrator’s Guide.

How many VMs should I put in a CG?

Most RecoverPoint for Virtual Machines replication operations such as enabling image access for a specific point in time, and failover are done per CG. Hence, they are performed on all the VMs that the CG protects.

If you need a single-VM granularity for these operations, then you should put each VM in a dedicated CG.

Before doing so, however, you should consider the following scale and performance factors:

• Only a single vRPA can replicate a CG. For example, if the I/O load that two VMs generate is greater than the load that a single vRPA replicates, you must protect these two VMs with two CGs, so that each CG can run on a separate vRPA.
• A RecoverPoint for Virtual Machines system supports up to 512 CGs. To protect more than 1024 VMs, protect several VMs with the same CG or deploy more than one RecoverPoint for Virtual Machines system.
• The number of CGs per vRPA affects RecoverPoint for Virtual Machines performance.
  • For all vRPA configurations (see Supported vRPA configurations) RecoverPoint for Virtual Machines achieves optimal performance when replicating fewer than 64 CGs per single vRPA.
  • For a silver or gold configuration, RecoverPoint for Virtual Machines achieves outstanding performance even when replicating 128 CGs per single vRPA. Under such load, the vRPA may exhibit a slight reduction in performance (< 10%).

Do I have to put all VMs that must be consistent together in the same CG?

The VMs that are replicated in a CG are always consistent. In some situations, however, due to performance considerations, it is not always possible to replicate the VMs in a single CG using a single vRPA. In this case, you can protect these VMs using several CGs, and put all these CGs in a group set with parallel bookmarking enabled. Group sets are easy to manage and guarantee consistency across the CGs that belong to them for every parallel bookmark.

A group set with parallel bookmarking enabled has the following limitations:

• It may contain up to 32 CGs.
• The minimum frequency for parallel bookmarks is 20 s.
• A CG cannot be in more than one group set with parallel bookmarking enabled.