Remove SAN disk/s while disk is in use (for DR testing) - Aix

This is a discussion on Remove SAN disk/s while disk is in use (for DR testing) - Aix ; Hi, While doing DR testing, we wanted to emulate a SAN issue and wanted to remove a SAN disk while the FS was in use (file being written continuously on the FS). We created a VG with single disk and ...

+ Reply to Thread
Results 1 to 6 of 6

Thread: Remove SAN disk/s while disk is in use (for DR testing)

  1. Remove SAN disk/s while disk is in use (for DR testing)

    Hi,

    While doing DR testing, we wanted to emulate a SAN issue and wanted to
    remove a SAN disk while the FS was in use (file being written
    continuously on the FS).

    We created a VG with single disk and a FS on it. Started a process
    (ping loopback > /test_fs/file.out &) to write to the test FS.

    When trying to remove the disk we got the error (obviously) that the
    disk is in use. Also tried removing the paths but got the same
    error....

    My question is, is there any way to remove a disk/path while it is
    being used.

    Thanks,

    Abhi

  2. Re: Remove SAN disk/s while disk is in use (for DR testing)

    On 2008-11-05, Abhi wrote:

    > My question is, is there any way to remove a disk/path while it is
    > being used.


    It would help a lot if you would give information about your setup. For
    example: what type of storage array are you using? Also, some more details
    about the test would be handy. The answer to your question could simply
    be: "Sure, just pull the cable." If you want to remove access to just one
    disk, more details are essential.

    --
    Jurjen Oskam

    Savage's Law of Expediency:
    You want it bad, you'll get it bad.

  3. Re: Remove SAN disk/s while disk is in use (for DR testing)

    > While doing DR testing, we wanted to emulate a SAN issue and wanted to
    > remove a SAN disk while the FS was in use (file being written
    > continuously on the FS).


    We did a similar test with disabling the port on the FC Switch.

    Regards,
    uwe



  4. Re: Remove SAN disk/s while disk is in use (for DR testing)

    On Nov 6, 1:35 am, Uwe Weber wrote:
    > > While doing DR testing, we wanted to emulate a SAN issue and wanted to
    > > remove a SAN disk while the FS was in use (file being written
    > > continuously on the FS).

    >
    > We did a similar test with disabling the port on the FC Switch.
    >
    > Regards,
    > uwe


    Hi,

    Yes, but the problem is, we do not have access to SAN Fabric or the
    Storage subsystem. The problem is these disks are not even VIO so we
    could have tried removing the mapping from VIO.

    As for setup, its not a very complex one, we have a IBM Storage
    (without SVC) and our test machine is using Dedicated IO for SAN
    disks. We have just 1 disk in the VG (as it is a test VG). OS is 53 TL
    07 SP 02. SDDPCM with MPIO for multipathing.

    each SAN disk has 4 paths 2 from (1 FCS). We have tried rmpath, rmdev
    (on both disk at card level with -R switch) we have also tried bring
    the adapters down at PCM level by pcmpath set adapter.....offline but
    it does not allows the last adapter to be turned offline as it is
    being used.

    cheers.....

  5. Re: Remove SAN disk/s while disk is in use (for DR testing)

    Abhi wrote:
    > On Nov 6, 1:35 am, Uwe Weber wrote:
    >>> While doing DR testing, we wanted to emulate a SAN issue and wanted to
    >>> remove a SAN disk while the FS was in use (file being written
    >>> continuously on the FS).

    >> We did a similar test with disabling the port on the FC Switch.
    >>
    >> Regards,
    >> uwe

    >
    > Hi,
    >
    > Yes, but the problem is, we do not have access to SAN Fabric or the
    > Storage subsystem.


    Hmm. In case of a real disaster, you or someone else running the SAN
    will need access. I recommend involving them in the DR planning and
    tests. Make them simulate outage of components (cabling, switch, storage
    system). Maybe they even have more scenarios. Like Uwe wrote, disabling
    selected ports should be enough to give the attached server a lifelike
    outage experience.

    Regards
    Joachim

  6. Re: Remove SAN disk/s while disk is in use (for DR testing)

    On Nov 6, 2:34 am, Abhi wrote:
    > On Nov 6, 1:35 am, Uwe Weber wrote:
    >
    > > > While doing DR testing, we wanted to emulate a SAN issue and wanted to
    > > > remove a SAN disk while the FS was in use (file being written
    > > > continuously on the FS).

    >
    > > We did a similar test with disabling the port on the FC Switch.

    >
    > > Regards,
    > > uwe

    >
    > Hi,
    >
    > Yes, but the problem is, we do not have access to SAN Fabric or the
    > Storage subsystem. The problem is these disks are not even VIO so we
    > could have tried removing the mapping from VIO.
    >
    > As for setup, its not a very complex one, we have a IBM Storage
    > (without SVC) and our test machine is using Dedicated IO for SAN
    > disks. We have just 1 disk in the VG (as it is a test VG). OS is 53 TL
    > 07 SP 02. SDDPCM with MPIO for multipathing.
    >
    > each SAN disk has 4 paths 2 from (1 FCS). We have tried rmpath, rmdev
    > (on both disk at card level with -R switch) we have also tried bring


    Have you used the -S switch for rmdev ? ( -S Stop the device but leave
    it configured)

    So i would give a

    $ chdev -l fcsX -R -S

    a try.

    At least the last time it worked for me with an EMC attached.

    Or search the net for
    "SDDPCM adapter failure question"
    http://unix.derkeiler.com/Mailing-Li.../msg00006.html

    Since a failed adapater should cause also a failover and there must be
    a procedure to replace a fc adapter.

    cheers
    Hajo

+ Reply to Thread