Cloning a VM with auto-RG selected together with changing VM settings can result in unnecessary creation of unwanted replication groups (i.e. replication group sprawl)

Products

• VMware vSphere ESXi

Issue/Introduction

To present a best practice to avoid creating unnecessary (and unused) replication groups.

Symptoms:

Replication group sprawl – e.g. replication groups are created that are never used.

Environment

VMware vSphere ESXi 6.7
VMware vSphere ESXi 7.0.x

Cause

When the user chooses auto-RG while cloning a VM residing on a  VVOL datastore ESXi uses a special auto-RG marker in the Storage Policy (SP) specification to indicate to the array that it should create a new replication group (RG). 

Here the cloning step will cause a VM to be created with a new RG (e.g. r1) when auto-RG is selected.
Next, if the user requests to have changes applied to the cloned VM, a ‘reconfigure’ step will be applied to the VM immediately after the clone using the same storage profile specification with the auto-RG marker thereby causing yet another RG (e.g. r2) to be created and assigned to the VM. The first RG (r1) is left unused.

Resolution

The issue can be avoided by sharing the below workaround externally as soon as possible.

Workaround:

• The issue can be avoided if the user does not change VM settings while cloning with auto-RG selected. In other words, when cloning a VM using auto-RG, the user should ensure that checkboxes corresponding to “Customize the operating system” or “Customize this virtual machine’s hardware” in “Select clone options” screen, are UNCHECKED.
• After cloning has completed, the user can modify settings of the cloned VM through the vSphere UI in a separate step.