3 Replies Latest reply on Aug 29, 2012 4:54 PM by Cindys-Oracle

    Solaris 11 LDOM zvol volsize problem

      hi expert,

      when we create Solaris 11 6 LDOMs on a T4-2 server , we face zvol volsize exceed what we set. the detail command like this:

      zfs create -V 300g dpool/ovm_ebs1_300g_zvol #create a zvol with 300G volsize
      ldm add-vdsdev /dev/zvol/dsk/dpool/ovm_ebs1_300g_zvol vol_ebs1@primary-vds0
      ldm add-vdisk ebs1_vdisk vol_ebs1@primary-vds0 ebs1_domain

      but when used for some time, this domain zvol`s volsize exceed 300G now.
      root@XIB1:~# zfs list
      dpool 1002G 194G 31K /dpool
      dpool/ovm_ebs1_300g_zvol *339G* 194G 301G -

      the detail attribute as follow:
      root@XIB1:~# zfs get all dpool/ovm_ebs1_300g_zvol
      dpool/ovm_ebs1_300g_zvol type volume -
      dpool/ovm_ebs1_300g_zvol creation Tue Aug 14 12:05 2012 -
      dpool/ovm_ebs1_300g_zvol used 339G -
      dpool/ovm_ebs1_300g_zvol available 194G -
      dpool/ovm_ebs1_300g_zvol referenced 301G -
      dpool/ovm_ebs1_300g_zvol compressratio 1.00x -
      dpool/ovm_ebs1_300g_zvol reservation none default
      dpool/ovm_ebs1_300g_zvol volsize 300G local
      dpool/ovm_ebs1_300g_zvol volblocksize 8K -
      dpool/ovm_ebs1_300g_zvol checksum on default
      dpool/ovm_ebs1_300g_zvol compression off default
      dpool/ovm_ebs1_300g_zvol readonly off default
      dpool/ovm_ebs1_300g_zvol zoned off default
      dpool/ovm_ebs1_300g_zvol copies 1 default
      dpool/ovm_ebs1_300g_zvol refreservation none default
      dpool/ovm_ebs1_300g_zvol primarycache all default
      dpool/ovm_ebs1_300g_zvol secondarycache all default
      dpool/ovm_ebs1_300g_zvol usedbysnapshots 37.7G -
      dpool/ovm_ebs1_300g_zvol usedbydataset 301G -
      dpool/ovm_ebs1_300g_zvol usedbychildren 0 -
      dpool/ovm_ebs1_300g_zvol usedbyrefreservation 0 -
      dpool/ovm_ebs1_300g_zvol logbias latency default
      dpool/ovm_ebs1_300g_zvol dedup off default
      dpool/ovm_ebs1_300g_zvol sync standard default
      dpool/ovm_ebs1_300g_zvol encryption off -
      dpool/ovm_ebs1_300g_zvol keysource none default
      dpool/ovm_ebs1_300g_zvol keystatus none -
      dpool/ovm_ebs1_300g_zvol rekeydate - default

      could somebody help me troubleshoot this issue?
      i think when i set zvol volsize as 300G, LDOM could not exceed this volsize value, but it exceed, what is the problem?
      Thank you!
        • 1. Re: Solaris 11 LDOM zvol volsize problem

          This is working as expected.

          When you create ZFS volume, a refreservation is automatically set that is a bit larger than
          the volsize you specified so that that the volume doesn't run out of space. In addition to
          sizing the volume, the volume must also account for changing metadata.

          This is described in zfs.1m under the volsize description, here:


          Thanks, Cindy
          • 2. Re: Solaris 11 LDOM zvol volsize problem
            Hi cindys,

            thank you very much for your help.
            but if I want to set an amount of disk space to this zvol, for example just 300G, how to set?
            what is the method?

            • 3. Re: Solaris 11 LDOM zvol volsize problem
              You will have to experiment with the volsize and provide a best guess .

              On my updated S11 system, creating a volume with 290gb provides a volume with a refreservation of 299gb:

              # zfs create -V 290g pond/vol1
              # zfs get refreservation pond/vol1
              pond/vol1 refreservation 299G local

              Thanks, Cindy