Migrating to thin provisioning VXVM

Migrating to thin provisioning

The SmartMove™ feature enables migration from a traditional LUN to a thinly provisioned LUN, removing unused space in the process.
To migrate to thin provisioning
  1. Turn on the SmartMove feature. Edit the file /etc/default/vxsf so that the variable usefssmartmove=all.
  2. Add the new, thin LUN to the existing disk group:
    # vxdisksetup -i THINARRAY0_02
    # vxdg -g datadg adddisk THINARRAY0_02
  3. Add the new, thin LUN as a new plex to the volume.
    NOTE: The file system must be mounted to get the benefits of the SmartMove feature.
    The following methods are available to add the LUN:
    • Use the default settings:
      # vxassist -g datadg mirror datavol THINARRAY0_02
    • Use the options for fast completion. The following command has more I/O impact.
      # vxassist -b -oiosize=1m -t thinmig -g datadg mirror \
  datavol THINARRAY0_02
      # vxtask monitor thinmig
    • Use the options for minimal impact. The following command takes longer to complete:
      # vxassist -oslow -g datadg mirror datavol THINARRAY0_02
  4. Optionally, test the performance of the new LUN before removing the old LUN.
    To test the performance, use the following steps:
    • Determine which plex corresponds to the thin LUN: 
      # vxprint -g datadg
      TY NAME                  ASSOC             KSTATE   LENGTH     PLOFFS  STATE     TUTIL0 PUTIL0
dg datadg                datadg            -        -          -       -         -       -
dm THINARRAY0_02      THINARRAY0_02   -          83886080   -       -         -       -
dm STDARRAY1_01       STDARRAY1_01    -          41943040   -       -OHOTUSE  -       -

v  datavol               fsgen            ENABLED   41943040   -       ACTIVE    -       -
pl datavol-01            datavol          ENABLED   41943040   -       ACTIVE    -       -
sd STDARRAY1_01-01    datavol-01      ENABLED   41943040   0       -         -       -
pl datavol-02            datavol          ENABLED   41943040   -       ACTIVE    -       -
sd THINARRAY0_02-01   datavol-02      ENABLED   41943040   0       -         -       -
      The above output indicates that the thin LUN corresponds to plex datavol-02.
    • Direct all reads to come from that LUN: 
      # vxvol -g datadg rdpol prefer datavol datavol-02
  5. Remove the original LUN. Note that ! is an escape on some shells; the example given avoids bash escape. 
    # vxassist -g datadg remove mirror datavol \!STDARRAY1_01
    # vxdg -g datadg rmdisk STDARRAY1_01
    # vxdisk rm STDARRAY1_01
  6. Grow the file system and volume to use all of the larger thin LUN: 
    # vxresize -g datadg -x datavol 40g THINARRAY0_02

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