Re: Replacing 7133 SSA Raid 5 disk without Hot Spare

From: Conran, John J (John.Conran@BHPSTEEL.COM)
Date: Wed Sep 17 2003 - 22:46:19 EDT


Hi Bruce

After replacing the offending drive with a spare, you'll need to
make the system believe it is the same drive that was replaced.

However, is it possible to simply add the replacement disk to the array as
a hot spare and have the array rebuild using the new disk?

I've replaced drives in the following manner with a RAID1 configuration but
have hot spares currently assigned for my RAID5.

Run lspv to check what disks can be seen by the OS.

Replace the desd SSA disk with a fresh unit.

Run cfgmgr command and see where the replacement disk now sits

For example

        # lspv

        hdisk0 000020216989fba7 rootvg
        hdisk2 000020216b34b8c0 datavg
        hdisk3 000020215f64a6ab datavg
        hdisk1 00002021417040f9 datavg
        hdisk5 00002021cfc04f91 raid1vg
        hdisk6 00002021cfc060e8 raid1vg
        hdisk7 00002021cfc071eb raid1vg
        hdisk12 0009144338b98b3c None
        hdisk15 0009144338addf4c None
        hdisk17 0009144338ab79f3 None
        hdisk18 00002021cfc082ed raid1vg
        hdisk19 00002021cfc0940e raid1vg
        hdisk20 00002021cfc0a523 raid1vg
        hdisk4 00002021673650e1 raid1vg
        hdisk25 000914433a79a1aa None
        hdisk8 000020212ec834a9 None The replacement disk

To rename it, find the connection location number of hdisk8 using the
command

        # lsdev -Cl hdisk8 -Fconnwhere

revealing

        000629D3C39700D

Remove this new hdisk8 using the command

        # rmdev -l hdisk8 -d

Rename the disk to the same hdisk number of the dead disk, e.g. hdisk21.

        # mkdev -p ssar -t hdisk -c disk -s ssar -w 000629D3C39700D -l
hdisk21

If it had not been removed previously, the disk should still be defined to
the RAID5 group

Check that the disk is still seen by running lspv.

Not sure if the RAID group needs to be taken offline and online at this
point
for rebuilding to commence or whether this can be initiated manually.

Hope this helps.

cheers
John Conran
Computer Systems Support
Plate & Strip
Integrated Markets
BHP Steel Ltd
The man who does not read good books has no advantage over the man who
cannot read them.
- Mark Twain

-----Original Message-----
From: Harvey, Bruce T. [mailto:BTHarvey@LMUS.LEGGMASON.COM]
Sent: Thursday, 18 September 2003 02:48 AM
To: aix-l@Princeton.EDU
Subject: Replacing 7133 SSA Raid 5 disk without Hot Spare

Folks,

Please direct me to archives if it's there, but we've got to swap out a disk
on a 7133 SSA arrays ... there was NO hot spare, and performance is now
degraded as the array has kicked the offending drive out. I've only dealt
with arrays that have hot spares before coming to this position, so I don't
have experience inserting a "live" disk.

What steps do I need to go through to get the drive going besides physically
pulling and inserting? Is everything AUTOMATIC? (*hah*) or do I set it up
as a Hot Spare or as a Candidate and execute some arcane command?

Many thanks and much apologies for the huge disclaimer.

Bruce T. Harvey
Legg Mason Wood Walker, Inc.
Corporate Technology - Tech. Svcs.
Red Run 2nd Floor - Owings Mills, MD
(410) 580-7383 - BTHarvey@LeggMason.com
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