On Mon 10 Jul, 2000, Frank Smith fsmith@hoovers.com wrote:
Wouldn't it be at least slightly risky to pull all your spares plus one of your data drives for the duration of a rebuild?
Yes. Therefore it's not really recommended.
You can of course replace all the spares as soon as the rebuild is suitably underway - which should allow for further rebuilds on other RAID groups if you have a multi-disk failure of that type.
If you have a real disk failure in the RAID group you just artificially pulled a disk from, then you start writing the apology emails and calling the ops to bring the tapes back on-site..
Overall, this creates additional work, and as laziness is a virtue, I, personally, wouldn't go pulling disks to neaten up my RAID groups.
(similar case: because the filer uses RAID4 not RAID5, and is a pretty smart cookie, you can achieve Great Things(tm) by not having a spare around and pulling the parity disk in each RAID group in a volume... the risk/benefit analysis is an exercise for the reader)
Frank -- End of excerpt from Frank Smith
mds@gbnet.net (Mark Simmons) writes:
On Mon 10 Jul, 2000, Frank Smith fsmith@hoovers.com wrote:
Wouldn't it be at least slightly risky to pull all your spares plus one of your data drives for the duration of a rebuild?
Yes. Therefore it's not really recommended.
It's a pity that ONTAP doesn't support some sort of "planned disc failure". The sort of thing I have in mind is duplication of the parity disc or one of the data discs of a RAID group on a spare disc, without having to fail the original one first. Then a failure of another disc in the group during the process could cause this duplication to be abandoned and the more urgent condition to be dealt with instead.
This would be useful when taking discs out of service that are showing problems but haven't actually failed yet.
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.
Chris Thompson wrote:
mds@gbnet.net (Mark Simmons) writes:
On Mon 10 Jul, 2000, Frank Smith fsmith@hoovers.com wrote:
Wouldn't it be at least slightly risky to pull all your spares plus one of your data drives for the duration of a rebuild?
Yes. Therefore it's not really recommended.
It's a pity that ONTAP doesn't support some sort of "planned disc failure".
...
This would be useful when taking discs out of service that are showing problems but haven't actually failed yet.
Isn't quite the same, but doesn't Veritas have an "evacuate" command?
-
Chris Thompson -
Dan Brown -
mds＠gbnet.net