Topic
6 replies Latest Post - ‏2012-11-22T17:53:35Z by ppereira
ppereira
ppereira
33 Posts
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Pinned topic MPIO not returning to highest priority path.

‏2012-11-20T17:42:37Z |
Hi; I'm running AIX 7.1 in a partition hosted in a p750 with dual vios.
Both VIOS present a SAN Lun to the partition.
This is the how the path to the disk is seen by the partition:

lspath -l hdisk0 -s available -F"connection:parent:path_status:status"
810000000000:vscsi0:Available:Enabled
810000000000:vscsi2:Available:Enabled

lspath -l hdisk0
Enabled hdisk0 vscsi0
Enabled hdisk0 vscsi2

lspath -El hdisk0 -p vscsi0 -a priority
priority 1 Priority True
lspath -El hdisk0 -p vscsi2 -a priority
priority 2 Priority True

If I remove the virtual target device at the VIOS which servers the lun trhough vscsi0 the path turns to Failed and the traffic moves to vscsi2, but, when I restore the virtual target devide and the path comes back to Enabled, the traffic does not comes back to vscsi0.

What should I do to make the traffic go back.

Regards and thanks in advance.
Updated on 2012-11-22T17:53:35Z at 2012-11-22T17:53:35Z by ppereira
  • SystemAdmin
    SystemAdmin
    6907 Posts
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    Re: MPIO not returning to highest priority path.

    ‏2012-11-20T20:11:56Z  in response to ppereira
    Run the varyonvg command.
    • ppereira
      ppereira
      33 Posts
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      Re: MPIO not returning to highest priority path.

      ‏2012-11-21T12:14:00Z  in response to SystemAdmin
      I would like it to return to the preferred path automatically. I've got another partition running AIX 6.1 and it works great. As far as I've checked the config is the same for both systems, maybe a bug on 7.1?

      Regards.
      Pablo.
      • SystemAdmin
        SystemAdmin
        6907 Posts
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        Re: MPIO not returning to highest priority path.

        ‏2012-11-22T15:36:23Z  in response to ppereira
        vscsi disk served by two VIO servers has set failover algorithm. From aix
        Link: documentation:

        When the algorithm attribute value is failover, the paths are kept in a list. The sequence in this list determines which path is selected first and, if a path fails, which path is selected next. The sequence is determined by the value of the path priority attribute. A priority of 1 is the highest priority. Multiple paths can have the same priority value, but if all paths have the same value, selection is based on when each path was configured.

        From above I don't expect an automatic failover to the preferred path. You didn't answer if manual intervention (the varyonvg) does the trick or not.
        • ppereira
          ppereira
          33 Posts
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          Re: MPIO not returning to highest priority path.

          ‏2012-11-22T17:53:35Z  in response to SystemAdmin
          I didn't try varyonvg because I want it to do the failback automatically. If it works on 6.1 don't see why it should not work on 7.1.
          I'm running 7100-01-03-1207. Right now I'm downloading the latest service pack and will try it.

          Regards and thanks.
          Pablo.
  • SystemAdmin
    SystemAdmin
    6907 Posts
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    Re: MPIO not returning to highest priority path.

    ‏2012-11-21T18:01:24Z  in response to ppereira
    What is the value of the hcheck_interval on yours disks on the lpar
    By default =0
    The value préconize by IBM is 60
    Read Redbook for précision
    • ppereira
      ppereira
      33 Posts
      ACCEPTED ANSWER

      Re: MPIO not returning to highest priority path.

      ‏2012-11-22T14:37:41Z  in response to SystemAdmin
      hcheck_interval 60

      I also tried 20 but it behaves the same.

      Thanks.
      Regards.
      Pablo.