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  • 1.  vSAN - Convert thick to thin disks

    Posted Jul 10, 2018 12:54 PM

    Hello everyone,

    As the title says, is there any way to convert a vmdk from Thick to Thin with the VM powered on?

    Also vmkfstools works on vSAN?

    Thanks in advance.

  • 2.  RE: vSAN - Convert thick to thin disks

    Posted Jul 10, 2018 06:31 PM

    Hello Lalegre

    This may depend on how the Thick is applied:

    - If you have applied an SP (Storage Policy) to the VMs/Disks with OSR=100(Object Space Reservation) then applying an identical SP with OSR=0 should Thin these instantly.

    - If this was applied at the 'Hard Disk' primitive level then unfortunately I think this will require a SvMotion of vsanDatastore to somewhere else (select Thin on destination) and then SvMotion back.

    - If the Data-Objects have proportionalCapacity=100 (functionally the same as OSR=100) applied to them but are using an SP with OSR=0 then this is a different story with a different fix that I have answered in a few other places on Communities and can advise on (if present).

    "Also vmkfstools works on vSAN?"

    Yes it does (assuming you are talking about -i clone), you have to specify a particular flag (-W vsan) so that it creates the resulting disk as a vSAN Object and not a -flat.vmdk - while this might Thin your disks without requiring an alternate datastore this can't be done powered on.