Post VLCR Test Failover Windows Server VMs May lose drive letters or retain 'ShadowCopy' attributes in environments leveraging High-Frquency and VSS-based backups on VSAN ESA or VVOL Storage

Products

• VMware Live Recovery

Issue/Introduction

Windows Server Guest OS reports missing drive letters, inaccessible partitions, or data integrity alerts after failover to the recovery SDDC. Affected volumes display persistent,
incorrect attributes (NoDriveLetter, ShadowCopy, or Read-only).

This issue occurs only when all the following conditions are met :
- Platform: VMs running on ESXi hosts 8.0.2 release or below
- Storage: vSAN ESA or VVOL Storage
- Situation: Simultaneous execution of High-frequency LWD snapshots in VMware
Cloud Live Cyber Recovery (VLCR) and VSS quiesced Third-Party backup VADP
snapshots

vSAN OSA or any other non-VVOL third-party storage arrays do not exhibit this
snapshot inconsistencies as they follow different mechanisms while capturing VSS
snapshots.

Environment

VMware Live Cyber Recovery 9.0.0.11
VMware Cloud Foundation 5.X
VMC on AWS SDDC Release 1.24vX
ESXi Server 8.0.2 or below

Cause

When a VSS-quiesced snapshot runs, the Windows OS performs "auto-recovery guest writes" to quiesce the file system. These writes apply restrictive attributes, specifically NoDriveLetter and ShadowCopy, to a separate volume for VSS snapshotting purposes. These attributes are designed to be transient and should revert immediately after the operation.

However, if a VLCR LWD snapshot occurs simultaneously, it may inadvertently capture these changes and mis-direct them to the main disk of the VLCR snapshot. Performing a DR failover to such a VLCR snapshot may prevent the VM from booting.

Resolution

The following steps to be performed to fix the issue only if your environment meets the three conditions described in the Introduction section:

- Upgrade vSphere ESXi in the environment to 8.0.3 or above. To upgrade the ESXi, please follow Upgrading ESXi
- In case Customer is using VMC on AWS SDDC, it should be upgraded to 1.26 release in both protected and recovery SDDC. Please reach out to VMC Support for assistance in upgrading the SDDCs.
- Perform a full ingest of all VMs that have third-party VSS backups enabled. This requires assistance from Broadcom Support. To open support request, please follow Create Support Request