3 Replies Latest reply on Jan 3, 2019 12:22 PM by TheBobkin

    Move Disk From 1 Disk Group To Another - Claim Disk or Add A Disk To The Selected Disk Group?

    mythumbsclick Novice

      Hi All

       

      I am running a 3 node Hybrid vSAN cluster. Each host has 2 disk groups (1 SSD and 5 HDs in each disk group). vSAN is set to to manual mode for adding disks to storage. Somewhere along the line a mistake was made where on 1 of the hosts, disk group 1 has 6 capacity disks and disk group 2 has 4.

       

      I need to move 1 disk from group 1 to group 2.

       

      So far I have done the following:

       

      1. Removed disk from disk group 1 - Full data evacuation (What would the difference have been if I chose ensure accessibility?).

      2. Allowed vSAN to resync objects

       

      I now want to move the disk over to disk group 2.

       

      1. Do I need to clean the disk first? If so should this be done at RAID level or vSAN (Storage Adaptors - Erase Partitions on the Selected disks)

      2. Do I need to "claim" the disk or "add a disk to the selected disk group"? (What is the difference?)

      3. Once the disk is back in the group, will vSAN start moving objects onto it or is it recommended to do a manual disk re-balance?

      4. Is there anything else I should be aware of?

       

      Many thanks

        • 1. Re: Move Disk From 1 Disk Group To Another - Claim Disk or Add A Disk To The Selected Disk Group?
          TheBobkin Virtuoso
          vExpertVMware Employees

          Hello mythumbsclick,

           

           

          "1. Removed disk from disk group 1 - Full data evacuation (What would the difference have been if I chose ensure accessibility?)."

          With EA(Ensure Accessibility) option it would wait for the clom repair delay timer (60 minutes default) to exceed before recreating the 2nd replica of data that resided on this disk - with FDM(Full Data Migration) it recreates replicas before removing the data on the device you are removing.

           

          "1. Do I need to clean the disk first? If so should this be done at RAID level or vSAN (Storage Adaptors - Erase Partitions on the Selected disks)"

          If the device was successfully removed then it should have no partitions on it - this can be verified in a number of ways including looking at it directly in /dev/disks/ , via Web Client Host > Storage Devices > Select device > Partitions or by seeing is it available to add to an existing Disk-Group: Cluster > Manage > vSAN > Disk Management > Select Disk-Group > '+' disk icon

          If these devices are/were individual RAID0 VDs per device as opposed to passthrough, you shouldn't need to reconfigure this.

           

          "2. Do I need to "claim" the disk or "add a disk to the selected disk group"? (What is the difference?)"

          Not sure if you are referring to autoclaim or what, just add it to the Disk-Group with less devices.

           

          "3. Once the disk is back in the group, will vSAN start moving objects onto it or is it recommended to do a manual disk re-balance?"

          No, by design it won't start moving stuff unless any devices are over 80% (default) and can move data here within compliance of the Storage Policy applied to the data - use manual rebalance via the GUI or RVC (where there are extra options) to initiate moving some data here immediately.

           

           

          Bob

          • 2. Re: Move Disk From 1 Disk Group To Another - Claim Disk or Add A Disk To The Selected Disk Group?
            mythumbsclick Novice

            Hi Bob

             

            Thank you for a rapid detailed response. Massively appreciated and meant I could confidently complete my maintenance over the festive period!

            • 3. Re: Move Disk From 1 Disk Group To Another - Claim Disk or Add A Disk To The Selected Disk Group?
              TheBobkin Virtuoso
              VMware EmployeesvExpert

              Hello mythumbsclick,

               

               

              More than happy to help.

              Though to you and anyone else reading this: if you have VMware/other support for vSAN, please don't be shy with logging a Support Request with us - even if it just for clarification or something you think is relatively trivial - we do not bite and prefer proactive guidance/clarification over fixing something broken as a result of improper procedure so you may actually be doing us a favour .

               

               

              Bob