FAQ

Frequently asked questions regarding vSNAP option.

1. NTFS and disk errors on Windows Event log

SYMPTOMS

User notices following event log recording on their Windows server event logs.

• Event ID: 50 NTFS Warning
  {delayed write failed} Windows was unable to save all the data for the file. The data has been lost. This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere
• Event ID: 57 NTFS Warning
  The system failed to flush data to the transaction log. Corruption may occur.
• Event ID: 137 NTFS Error
  The default transaction resource manager on volume \\?\Volume{804941w8-6028-31x0-a165-223056ae001d} encountered a non-retryable error and could not start. The data contains the error code.
  
• Event ID: 140 NTFS Warning
  The system failed to flush data to the transaction log. Corruption may occur in VolumeId:<> DeviceName: \Device\HarddiskVolume<>.(A device which does not exist was specified.).
  
• Event ID: 157 Disk Warning
  Disk x has been surprise removed.

CAUSE

This happens because vSNAP backup job creates a temporary disk as part of its snapshot procedure, and the disk removal will show up as logged errors in the Event Viewer.

Resolution

When running a Windows Virtual Machine using quiesced snapshot* on a backup schedule, it is normal to see several Disk and NTFS errors in Windows Event Viewer. You can ignore this event log since this is by design the way VMware and Microsoft's handles agent-less backup.

*quiesced snapshot:

Microsoft's VSS aware plugin that asks applications to enter a safe state before the snapshot occurs. This is to prevent grabbing things like Exchange and SQL in an inconsistent state.

On a side note, If your Windows application environment needs more mission critical backup, we recommend to switch from vSNAP (this is the most basic backup method) to agent-based backup or more application-aware backup methods.