Re: reconstructing a RAID5 volume taking FOREVER?!?

indirectly .. upgrade from ML4 ASAP


Joe D. wrote:
Hello all;

I have replaced a 148 GB disk in an on-board array in my 9113-550
server. Server is running AIX5.2, ML04. The raid controller card on
sisioa0 is a PCI-X Dual Channel U320 SCSI RAID Adapter. The reconstruct
is taking a LONG time; going on 6.5 hours now, and only 73% complete.

I used the normal 'Hot-Plug' procedures as outlined on the IBM site,
then followed the instructions outlined in the "PCI-X SCSI Raid
Controller: Reference Guide for AIX" to reconstruct the RAID disk. The
smit.log file shows the following command:

Command_to_Execute follows below:
>> sisraidmgr -R -z'pdisk1'

According to the above reference guide this is correct (I was worried
that I may be wiping out my entire RAID group!). The pdisk1 IS indeed
the disk that failed, (and we 'flashed the LED, etc. to ensure that we
did indeed actually REPLACE the failed one).

I found a post from another person in this forum, stating "...God help
you if you ever have to reconstruct (vs resilvering a raid10 set) one
of your 146GB drives after a failure. Will take forever, and render
your machine useless during the reconstruction.....".

I find this hard to swallow that this is how thing are going to be; one
of the benefits of RAID5 is supposedly to provide on the fly recovery
and reconstruction. SOME degradation is to be expected, but I have
never seen a reconstruct take this long on ANY other platform. We're
luckily not in production on this server as yet, but we will be soon,
and I shudder to think what will be the effects of a failed drive in
future.

Don't take the above the wrong way; I'm not knocking AIX, I'm just
astounded that this is taking this long. Is this normal? Is there
anything I can do to improve this?

Thanks for listening; hope this finishes sometime today. : (

Joe D.

.

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