Enabling VMware Tools debugging inside the Windows OS causes quiescing failure.

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

1. Quiescing fails when enabling tools debugging within the OS.

2. This happens with both manual quiescing from the vSphere Client and quiescing triggered by the backup solution as a part of the backup activity.

3. Inside the VSS logs, you see that the VSS is unable to identify the recovery volume that is included in the VSS SnapshotSet during the VSS process and as a result the VSS errors out with the IDispatch error #8468.

Unexpected result from QueryStatus(): 0x80042314
[YYYY-MM-DDT15:24:25.114Z] [ warning] [vmvss] [30308] CVmSnapshotRequestor::WaitForOperation():3677: Async operation result: IDispatch error #8468
[YYYY-MM-DDT15:24:25.114Z] [ debug] [vmvss] [30308] CVmSnapshotRequestor::DoSnapshotSet():2138: failed call: ret = WaitForOperation(async), result = 0x80042314
[YYYY-MM-DDT15:24:25.114Z] [ debug] [vmvss] [30308] CVmSnapshotRequestor::Finalize():2920: enter
[YYYY-MM-DDT15:24:25.145Z] [ debug] [vmvss] [30308] CVmSnapshotRequestor::UnmountSnapshotVolumes():2742: enter
[YYYY-MM-DDT15:24:25.145Z] [ debug] [vmvss] [30308] VDSHelper::ForEachVolume():332: enter
[YYYY-MM-DDT15:24:25.145Z] [ debug] [vmvss] [30308] VDSHelper::ForEachVDSPack():250: enter
[YYYY-MM-DDT15:24:25.145Z] [ debug] [vmvss] [30308] VssProvider_IsDiskSupported():81: Mismatched vendor id: NECVMWar
[YYYY-MM-DDT15:24:25.145Z] [ debug] [vmvss] [30308] VssProvider_IsDiskSupported():108: VMware disk uuid not found: 6000c213-52cc-732c-9bdd-cd2be5e64c88

 

4. The application log of the OS at the time of the issue shows VSS erroring out.

Environment

VMware vSphere ESXi 7.0.x
VMware vSphere ESXi 6.7

Cause

"vmvss.handler = file" inside the tools.conf makes logging as continuous file write during VSS quiescing process, while VSS expects that the IO should be quiesced too which can easily cause quiescing failure.

This is an expected behavior.

Resolution

Set the “vmvss.handler = vmx” instead of the default value "file", if you want to use tools debugging and take a quiesce snapshot at the same time.

Additional Information

https://kb.vmware.com/s/article/1007873

Impact/Risks:

Manual and automatic quiescing during backup fails when using VMware Tools debugging inside the Windows OS.