I'll second that. It's easy to pull a drive and hope everything is OK,
but the risk is very high. If you were to do this though, ensure that
you're array is less than 50% full. Even on a busy system, the less full
you are, the less there is to rebuild and the better off you'll be.
Not to mention, the NCR controllers you have, are they just scsi and
you're using md devices across 2 controllers? If so, watch out with that
too. Unless you're using RAID 5/1, you could easily hurt your
performace, and the box could be un-useable for quite some time.
Also, if you're array is external, and you have real hardware RAID, take
the afformentioned advice below and let LSI prove it to your boss.
On Mon, 2001-12-17 at 20:30, Matt Avila wrote:
> John,
>
> If memory serves me, the NCR controllers are OEM'd by LSI (Metastor).
> The RAID parity computation and rebuild should be handled by the
> external array. Your host only sees what it thinks are disks, attached
> however (fibre / SCSI)... it makes no difference. Your creating LUN's on
> the array and presenting these to the host. It only knows disk.
>
> The rebuild will be completely transparent to the host, so pull away!
> CAUTION however - IF you've got production data on this array, you WILL
> be running exposed while a re-build takes place. Depending on the size
> drives and the priority established for the rebuild, this can take
> awhile (I've seen 73GB drives take 18+ hours on a busy system). Should a
> second drive truly fail, you will loose the entire RAID set unless the
> rebuild is finished.
>
> As opposed to simply pulling the drive to impress your boss, why not ask
> your boss why he needs to be impressed. Take that answer back to your
> storage vendor and let them prove it. That way if anything goes wrong,
> its not your butt.
>
> -----Original Message-----
> From: owner-linux-xfs@xxxxxxxxxxx [mailto:owner-linux-xfs@xxxxxxxxxxx]
> On Behalf Of Westerdale, John
> Sent: Monday, December 17, 2001 9:11 PM
> To: linux-xfs@xxxxxxxxxxx
> Subject: Pulling disk out of the RAID 5 Array?
>
>
> Hello all!
>
> Am tasked with proving the RAID-5 recovery strategy!
>
> Have a Dual PII-400/ with external array (compaq storage F2) connected
> via two ncr53C875 controllers... Box does OK! 8X9-GB drives provide 63
> usable GB, and has been behaving itself for the past week or so.
>
> My Boss wants to pull out a drive, and put an unformatted one in and see
> how it rebuilds!
>
> A realistic test for the dark day.... The external drive is all data. OS
> is inside... (does this matte?)
>
> Anything to watch out for when rebuilding is underway? Can I adjust
> /etc/raidtab to rebuild faster? How does XFS compare to rebuilds on
> other file systems?!?!
>
> My last question was great!!! thanks for the responses... Seems the 2 GB
> limit is in software settings and history more than programming
> techniques.. Cant we all just do > 2 GB ?
>
> THanks a Bunch!!!
>
> JDW
>
--
Austin Gonyou
Systems Architect, CCNA
Coremetrics, Inc.
Phone: 512-698-7250
email: austin@xxxxxxxxxxxxxxx
"Have regard for your name, since it will remain for you longer than a
great store of gold."
Ecclesiastes, Aprocrypha
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