ASM "disk" replacement
Date: Thu, 7 May 2009 14:57:43 -0500
Message-ID: <EF73D0391D16CD4EA683766122FE9DD775A2CF_at_OMU-EXCH01.solutionary.com>
We are using ASM for 10.2.0.4 RAC on Linux x86-64 and will need to replace a number of disks in the storage array.
I am wondering if anyone here has had any "interesting" experience with this sort of thing - good or bad.
This can also be a sanity check on my embryonic "plan". I just heard about the need for this today and need to come up with a plan. We don't have to do this soon, but it absolutely must be done well before the end of the year.
This may be complicated (or simplified) a bit by the fact that we have a sort of "minimal ASM" setup. ("New-fangled gizmos anywho - don't entirely trust 'em." - the OraSaurus in me says.)
The basics:
Only datafiles and tempfiles are on ASM - in a single diskgroup.
Redo is on "real" raw devices, not ASM. Archive destinations on OCFS2 filesystem. RMAN backups to NAS.
2.5+ TB database - hot, mostly with massive 24xforever inserts. (This beast generates 200+ GB of archive on a slow day.)
The six existing ASM "disks" are actually RAID-10 sets striped and mirrored in hardware - about 500 GB each.
Only "external redundancy" in ASM.
Physical (exclusive) standby also on ASM - different hardware and location, but same layout, but a different diskgroup name.
[Network link between primary and standby is rather busy - bandwidth
about 50% utilized just by log shipping.]
Notable downtime is not an option.
In theory, this should be easy (famous last words) - alter diskgroup ... add <some new "disks"> drop <some old "disks">;
Adding the new replacement "disks" (with similarly sized/performing hardware RAID-10 sets) and dropping the old ones in a single "alter diskgroup" command *should* minimize the ASM rebalancing.
We would likely do this first on the standby, then on the primary once the standby "reorg" is complete.
[Hopefully, we will have a complete production mirror - RAC, standby and
all, with somewhat weaker hardware though - to test all this on first.]
So, does anyone have any relevant experiences, horror stories, caveats, hearsay, et cetera to share?
Thanks for any info!
Don Granaman
-- http://www.freelists.org/webpage/oracle-lReceived on Thu May 07 2009 - 14:57:43 CDT