Virtual Machine cannot take snapshot after extending virtual disk size

Products

• VMware vSAN

Issue/Introduction

Symptoms:

This issue only happens on CBRC enabled Virtual Machine under vSAN ESA datastore.

Virtual Machine snapshot fails with the below error message:

"DiskLib_CreateChild: failed to create digest child disk: The specified feature is not supported by this version"

For powered-on VM, the error message is in VMware log under the Virtual Machine namespace, such as:

"/vmfs/volumes/vsan:52975d1681d01f40-305fba8535efd2d8/3bd10064-1490-ee1b-4745-b02628350470/vmware.log".

For powered-off Virtual Machine, the error message is in hostd log under "/var/run/log".

A flat digest vmdk of the extended virtual disk is newly created under the Virtual Machine namespace after extending the virtual disk size, such as:

"/vmfs/volumes/vsan:52975d1681d01f40-305fba8535efd2d8/3bd10064-1490-ee1b-4745-b02628350470/snapshots-centos7-1677775162.484266_2-digest-flat.vmdk"

The file snapshots-centos7-1677775162.484266_2-digest-flat.vmdk appears under VM's namespace /vmfs/volumes/vsan:52975d1681d01f40-305fba8535efd2d8/3bd10064-1490-ee1b-4745-b02628350470/ after extending the disk snapshots-centos7-1677775162.484266_2.vmdk

 

Environment

VMware vSAN 8.0.x

Cause

In the process of extending a virtual disk, it hardcodes the digest vmdk create type to a flat file, but for native snapshot supported datastores, such as vSAN ESA, digest vmdk create type should be object instead of file. As a result, the digest type is inconsistent.

Resolution

Currently there is no resolution. This will be fixed in the future release.

Workaround:

To workaround the issue, please renable CRBC on the Virtual Machine.

1. Disable CBRC on the Virtual Machine.

2. Enable CBRC on the Virtual Machine.