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VMWare Virtual Servers - Snapshot Removal
Posted by James O'Linger on 21 June 2017 07:38 AM

Dear VM Admins,

As part of an effort to improve the VMWare environment in the Enterprise and Cloud Services department, please note that beginning July 1st, 2017, VM snapshots older than 90 days will be automatically removed.  We have had numerous snapshots running much longer than that and they are getting out of control.  Snapshots are a TEMPORARY solution to issues that you may be having with your production VM server.  Here are the best practices from VMWare regarding VM snapshots from https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1025279:

Please follow these best practices when using snapshots in the vSphere environment:

  • Do not use snapshots as backups. The snapshot file is only a change log of the original virtual disk, it creates a place holder disk, virtual_machine-00000x-delta.vmdk, to store data changes since the time the snapshot was created. If the base disks are deleted, the snapshot files are not sufficient to restore a virtual machine.
  • VMware recommends only a maximum of 32 snapshots in a chain. However, for a better performance, use only 2 to 3 snapshots.
  • Do not use a single snapshot for more than 24-72 hours (Compared to VMWare’s recommendation, we feel that 90 days is more than adequate). The snapshot file continues to grow in size when it is retained for a longer period. This can cause the snapshot storage location to run out of space and impact the system performance.
  • When using a third-party backup software, ensure that snapshots are deleted after a successful backup. Note: Snapshots taken by third party software (through API) may not appear in the Snapshot Manager. Routinely check for snapshots through the command-line.
  • Ensure that there are no snapshots before:
    • Performing Storage vMotion in vSphere 4.x and earlier environments. Note: vSphere 5.0 and later support Storage vMotion with snapshots on a virtual machine.
    • Increasing the virtual machine disk size or virtual RDM. Increasing the disk size when snapshots are still available can corrupt snapshots and result in data loss.

Thank you for working with the ITS division on improving our virtual environment!  Together, we can do great things.

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