Your Go-To Guide for Safe Recovery from VMware Data Loss

Thursday, January 6, 2011 by The Data Experts


Tips on How to Safely Recover From VMware Data Loss

  • Restore backups to a different volume. This ensures that all important files are good on the backup before possibly overwriting data on the active volume.
  • If there is a RAID problem, test the backup by restoring it to a different location or image each drive from the RAID before attempting a rebuild. Sometimes a RAID rebuild does not work correctly and can make the problem worse.
  • Do not create any new files on the disk needing recovery or continue to run virtual machines until the important data is recovered. New files can overwrite the files that need recovery if restoring the backup fails. VMs using snapshots and thin provisioned virtual disks that are still in use after the data loss can also overwrite files that need recovery.
  • Do not run FSCK or CHKDSK file system repair tools on a virtual disk unless a good backup has been validated by restoring it to a different volume. These repair tools assume that there is a good backup of the data and can overwrite file pointers to make a file system consistent. If desired, these tools can be run in read-only mode to find any major corruption before repairs are made.

Tips on How to Improve Data Recovery Service Success

  • Do not delete any additional files prior to a data recovery of deleted data. Additional deleted files can complicate the data recovery.
  • Do not try recovery software unless you are sure it will not write anything to the disk that needs recovery. Some recovery software will attempt to write to the source disk and could damage later recovery attempts.
  • If one virtual disk needs recovery but others are still running from the same volume and cannot be shut down during the recovery, clone or migrate them to another volume. If a deleted virtual disk or snapshot needs recovery, it is best to copy or clone the virtual machines instead of migrating them so they are not found as part of the deleted recovery.
  • Shutdown or migrate any other active VMs on the same volume that are thin provisioned or are using snapshots. Any writing to the new blocks on the volume can overwrite recoverable data.