vSAN - Deduplication is not showing any space savings
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vSAN - Deduplication is not showing any space savings


Article ID: 326561


Updated On:


VMware vSAN


  • vSAN cluster with deduplication and compression enabled is seeing no result in the deduplication and compression overview.
  • Summary tab screen reports that no space is being saved by deduplication and compression.
  • You see low deduplication ratio.


This issue occurs because objects are 100% reserved.


  • Run this command on any of the hosts as it will display all disk information in the cluster:
    • esxcli vsan debug disk list.
    • The output from the command above is reporting all disks with high amount of reserved space.
  • To fix this issue, ensure the storage policies are not set for object space reservation: 100% (Thick provisiong):
    • Click Menu > Policies and Profiles > Click VM Storage Policies > search for the vSAN Storage Policy or the custom policy used and select it, this will display the policy details and show it has 100% reservation:image.png

  • You can run this command on RVC to show disks stats as well and see object space reservation:
    • vsan.disks_stats <cluster>