ESXi

 View Only
  • 1.  old snapshots

    Posted Nov 19, 2013 12:31 PM

    Are there any formal vmware documents that discuss the impact of not removing old snapshots of virtual machines - i.e. performance issues they can cause on the VM itself?

    Our admin doesnt seem to see these as a risk at all - but I have read old snapshots can affect the performance of the VM - but I cant seem to locate any formal documentation where VMware themselves discuss the potential issues of not removing old snapshots. To demonstrate its not an old wives tale.



  • 2.  RE: old snapshots
    Best Answer

    Posted Nov 19, 2013 12:55 PM

    You are absolutely correct ... this not only impacts the VM, but also the backend storage array which could affect other VM's too.

    http://kb.vmware.com/kb/1025279

    • An excessive number of delta files in a chain (caused by an excessive number of snapshots) or large delta files may cause decreased virtual machine and host performance.

    http://pubs.vmware.com/vsphere-50/topic/com.vmware.vsphere.vm_admin.doc_50/GUID-53F65726-A23B-4CF0-A7D5-48E584B88613.html

    • Snapshots can negatively affect the performance of a virtual machine. Performance degradation is based on how long the snapshot or snapshot tree is in place, the depth of the tree, and how much the virtual machine and its guest operating system have changed from the time you took the snapshot. Also, you might see a delay in the amount of time it takes the virtual machine to power-on. Do not run production virtual machines from snapshots on a permanent basis.

    Message was edited by: Jon Munday - additional URL added



  • 3.  RE: old snapshots

    Posted Nov 19, 2013 02:54 PM

    jrmunday already mentioned the important aspects - let me add one point from a recovery point of view.

    All vmdk types that require a working VMFS journal are more fragile than those types that dont.
    That means VMs that use snapshots, thin provisioned vmdks or sesparse vmdks are unusable when the VMFS journal is unreadable.
    Thick provisioned vmdks can still be usable even without the VMFS journal.