Re: SSA RAID for a newcomer!

From: Bill Verzal (BVerzal_at_KOMATSUNA.COM)
Date: 10/20/04

  • Next message: Nguyen, Joseph: "Re: SAN Question" 
    Date:         Wed, 20 Oct 2004 10:08:36 -0500
To: aix-l@Princeton.EDU

    I just got bit by a SSA rule a few months back.

    If there are more than 2 SSA adapters in any loop, you cannot create RAID
    arrays on that loop. Keep that in mind.

    BV

    -------------------------------------
    There's no place like /home

    Bill Verzal
    Project Leader, Komatsu America

    (847) 970-3726 - direct
    (847) 970-4184 - fax

                 "Green, Simon"
                 <Simon.Green@EU.A
                 LTRIA.COM> To
                 Sent by: IBM AIX aix-l@Princeton.EDU
                 Discussion List cc
                 <aix-l@Princeton.
                 EDU> Subject
                                           SSA RAID for a newcomer!

                 10/20/2004 09:08
                 AM

                 Please respond to
                      IBM AIX
                  Discussion List
                 <aix-l@Princeton.
                       EDU>

    I'm quite familiar with SSA, but have never configured it as RAID, (apart
    from through LVM). I am now interested in looking at RAID for one of our
    systems.

    The servers is an S7A with two I/O drawers: the adapters are split over
    both
    drawers. It's running AIX 4.3.3 at the moment. (It will eventually be
    migrated to AIX5L but not in time for this.)

    This server has about 1TB of SSA disks - a mix of 9, 18 and 36GB - going
    through six SerialRAID adapters. It's configured as twelve distinct loops:
    no shared adapters. (It's in an HACMP cluster, so actually they ARE
    shared,
    but we're going to remove that soon.) Each loop has half of a 7133-D40: A
    &
    B loop for a single adapter are on the same drawer. All of the adapters
    have fast-write cache. There is a seventh adapter which is unused at
    present.

    All LVs are mirrored, using LVM. There are four separate VGs. There is
    very little spare disk capacity, although I have a couple of empty 18GB
    disks and might be able to borrow some disks from another project, if I
    time
    it right.

    I don't think it will be possible to create RAID disks in the existing VGs
    as the PP size is only 64MB, and most of the VGs have c20 disks. That
    suggests I'm looking at backup/restore.

    I haven't decided how many RAID arrays I want, yet.

    I'm looking around for somewhere I can have a play, but so far can't find
    anywhere suitable.

    Before I get too deep into this, can anyone foresee any possible problems I
    might encounter? 

    --
Simon Green
Altria ITSC Europe Ltd
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  • Next message: Nguyen, Joseph: "Re: SAN Question"

    Relevant Pages

    • SSA RAID for a newcomer!
      ... I'm quite familiar with SSA, but have never configured it as RAID, (apart ... through six SerialRAID adapters. ... All LVs are mirrored, using LVM. ... disks and might be able to borrow some disks from another project, ...
      (AIX-L)
    • Re: SSA RAID for a newcomer!
      ... Update your bookmarks, Joseph, at least now your link redirects here: ... > I'm quite familiar with SSA, but have never configured it as RAID, ... > through six SerialRAID adapters. ... > disks and might be able to borrow some disks from another project, ...
      (AIX-L)
    • Re: SSA RAID for a newcomer!
      ... You can visit the SSA support site at: ... I'm quite familiar with SSA, but have never configured it as RAID, ... through six SerialRAID adapters. ... disks and might be able to borrow some disks from another project, ...
      (AIX-L)
    • Re: SSA RAID for a newcomer!
      ... Update your bookmarks, Joseph, at least now your link redirects here: ... SSA RAID for a newcomer! ... > going through six SerialRAID adapters. ... > 18GB disks and might be able to borrow some disks from another ...
      (AIX-L)
    • Re: HACMP/SSA and RAID5 on "ADVANCED SERIALRAID PLUS ADAPTER"
      ... > can have a maximum of two adapters on the same loop. ... > RAID adapters in the same loop, then the RAID cache is mirrored between ... I can only use AIX mirroring on AIX level. ...
      (comp.unix.aix)