VG mirroring - Aix

This is a discussion on VG mirroring - Aix ; Hi, my company purchased a new storage array, and i need to migrate data from the old array to the new one. i'd like to know if there is a way to migrate the data online, with host-based mirroring. can ...

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Thread: VG mirroring

  1. VG mirroring

    Hi,
    my company purchased a new storage array, and i need to migrate data
    from the old array to the new one.
    i'd like to know if there is a way to migrate the data online, with
    host-based mirroring.
    can i add a new volume or set of volumes to an existing volume group,
    perform a mirror and disconnect the old volumes without downtime?

    instructions will be very appreciated.
    thanks,
    yaron

  2. Re: VG mirroring


    IBM has a thing called SVC for storage virtualization. It would be ideal
    for online migration. It would be very expensive though to get it.

    They have options to "rent" it for this kind of activities. You will
    have to check with IBM for details.

    I think there are similar products available from many vendors.


    --
    mrrijo
    ------------------------------------------------------------------------
    mrrijo's Profile: http://fantasticunix.com/forum/member.php?userid=21
    View this thread: http://fantasticunix.com/forum/showthread.php?t=506334


  3. Re: VG mirroring

    pomikister schrieb:

    > can i add a new volume or set of volumes to an existing volume group,

    yes. However, there are some points to consider
    - normal VGs have a max of 32 disks (1)
    - big VGs have a max of 128 disks (1)
    - normal VGs and big VGs have a fixed number of PPs per disk (1016)
    The new disk cannot be bigger/cannot have more PPs (1)
    - scalable VGs have a max of 1024 disks, no (better very high)
    max PPs per disk).
    (1) you may change the VG factor, making a normal/big VG to be able to
    hold 2032 PPs (or 3*1016, or...). But then the max number of disks gets
    half (1/3....)
    Last but not least, you can convert a normal to a big to a scalable VG.
    But be sure to have a good backup and the lastest AIX levels. If some
    bug hits you :-( See man chvg for details. You may need a free PP per
    disk to be able to holg the bigger VGDA data.

    > perform a mirror and disconnect the old volumes without downtime?

    you want to migratepv. Again, see the man page.
    And prior disconnecting the old disks, better remove them from the VG.

    All this can be done using smit, but read the man pages to understand
    what you are doing before you actually do it. A point you may start:
    http://publib.boulder.ibm.com/infoce.../migcontpv.htm

  4. Re: VG mirroring

    On Jul 8, 7:42*pm, mrrijo mx.forums.yourdomain.com.au> wrote:
    > IBM has a thing called SVC for storage virtualization. It would be ideal
    > for online migration. It would be very expensive though to get it.
    >
    > They have options to "rent" it for this kind of activities. You will
    > have to check with IBM for details.
    >
    > I think there are similar products available from many vendors.
    >
    > --
    > mrrijo
    > ------------------------------------------------------------------------
    > mrrijo's Profile:http://fantasticunix.com/forum/member.php?userid=21
    > View this thread:http://fantasticunix.com/forum/showthread.php?t=506334


    I think, mirroring would be a good option, though it would take time
    depending on your data size.

    Alternatively, you can also do migratepv if your number of PVs are
    less. But before doing this, just check your current OSlevel + TL and
    go thru the list of APARs for your level. We had an issue with
    migratepv once and had to do a lot of cleaning (ofcourse, without
    loosing data). In short, if you choose this method, you will have to
    do a lot of research.

    I am not sure about SVC solution because as far as I remember, you
    have to create managed disk groups and then virtual disks from those
    mdiskgrp/s and then map them thru SVC to the destination server once
    that happens I am not sure how you would remove SVC (if you are
    renting it...)

    cheers....

  5. Re: VG mirroring

    On Jul 8, 4:24 pm, pomikister wrote:
    > Hi,
    > my company purchased a new storage array, and i need to migrate data
    > from the old array to the new one.
    > i'd like to know if there is a way to migrate the data online, with
    > host-based mirroring.
    > can i add a new volume or set of volumes to an existing volume group,
    > perform a mirror and disconnect the old volumes without downtime?
    >
    > instructions will be very appreciated.
    > thanks,
    > yaron


    Depending from the AIX version and Disk size the steps are
    1) add the new disk to the current Volume Group (VG)
    $ man extendvg
    2) migrate the data to the new disk - disk or lv based
    $ man migratepv
    3) Remove the old disk from the VG
    $ man reducevg

    hth
    Hajo


    1)

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