From: Tom Wood (twood@rezlink.com)
Date: Wed Feb 05 2003 - 11:05:19 EST
We have/are implementing the same scenario - a 7026-6m1 connected to a
7133-t40 via 2 controllers with qty 16 18.xgb drives and a 7026-6h1
connected to the same SSA enclosure running Oracle 8.1.7. (In addition,
the 6h1 has a local expansion cabinet for its additional disk connected
via a scsi controller when not needed by the HACMP environment.)
Our final configuration was to use software mirroring and stripping of
the disks due to performance concerns. The raid 0+1 implementation was
giving us the necessary throughput we needed.
One of the considerations that affected our decision was the limitation
of the number of controllers that could be connected in some of the raid
configurations - you may want to review that.
As far as the raw devices are concerned, I'm not sure what limitations
that may bring in related to the SSA controllers and loops.
As always, the redbooks such as Advanced SerialRAID Plus Adapter
Planning Guide has a lot of info.
Tom
-----Original Message-----
From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU] On Behalf Of
BSARMA
Sent: Tuesday, February 04, 2003 6:32 PM
To: aix-l@Princeton.EDU
Subject: RAID5 with SSA disks
Greetings
We have our IBM RS6000s (H70) with SSA disks with HACMP 2 node Cluster
we have 2 SSA controllers in each box.
We are settingup Oracle RAC 2 node cluster for load balancing and
failover.
Our application is OLTP.
We want to setup RAID5 using all the controllers (2+2), so that if
Controller1 on Server1 fails it can use Controller2 on server1 and both
the controllers take the io. Same with the other cluster.
But the IBM Service people say that we can not have 2 controllers in
RAID5,
please advice.
I appreciate if you can point me towards some documentation or papers.
If this is not possilbe we would like to have Raid 0+1 and Raid5
together
some of the orale stuff (redologs, controlfiles, temporary tablespace
(may be it needs raid 0), rollback segments (undo tablespace).
All these days we have been using raid5, if we plan to use raid 0+1 are
there any plus or negative points to watch.
I have been reading the material about raid, but everybody talks as File
systems. Since We have to use RAW partitions for Oracle OPS or RAC.
I appreciate your experiences or your notes.
Regards and Thanks
BN
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