From: David J. DeWolfe (sxdjd@ts.sois.alaska.edu)
Date: Thu Feb 03 2005 - 16:36:02 EST
All;
We, the University of Alaska, are running several Oracle 9i databases on a
pair or GS1280's which are each hardware partitioned in to 2 identical
nodes of 16G RAM and 8 - 1.1Ghz CPU's each. All 4 nodes are clustered
together via dual memory channel rails. The storage in use is an EVA 5000
running VCS 3.010 (soon to be upgraded to 3.020) connected to the nodes via
dual redundant fabrics. Our 2 largest production Oracle databases have
SGA's of ~2G. We have several other pre-production databases running on the
cluster which are much smaller.
When we went live with this setup almost a year ago HP support indicated
that big pages memory allocation was where we wanted to be, but at that
time (Patch Kit 2 days) there were issues with big pages and they
recommended that we use granularity hints. We did so, wiring 2G of memory
on each node via setting rad_gh_regions[0] through rad_gh_regions[7] to 512
in sysconfigtab.cluster. We also set gh_fail_if_no_mem = 0 to allow our
databases to consume > 2G should the need arise. After applying PK3 we
began looking at implementing big pages until we saw all the big page
related fixes in the PK4 release notes not to mention the summary at:
http://www.ornl.gov/lists/mailing-lists/tru64-unix-managers/2004/03/msg00029.html
which talks about PK3 breaking big pages. We have recently applied PK4 and
are once again in the process of looking at implementing big pages. We've
been rock solid using granularity hints and I muss confess that we're a
little bit gun shy regarding big pages. We have had big pages enabled on 1
of our internal test clusters (4 DS10's) but the size of the test databases
and load on the DS10's pales in comparison to the production GS1280 cluster.
Other than hoping to learn from other's experiences I do have 1 specific
question. I presume that given our 4 node cluster we could implement big
pages 1 node at a time which, as I see it, would give us the ability to run
some pre-production databases using big pages. If all went well with that
we could relocate one of our production databases to a node using big pages
and if all did not go well with that we could relocate it back to one of
the nodes using granularity hints. If all did go well, we'd just continue
to implement big pages on the remaining nodes.
I would be interested in hearing from anyone, particularly anyone running
Oracle, who is running 5.1b and who has implemented big pages. Any advise,
thoughts, concerns, do's, don'ts, etc would be most welcome.
TIA and I will summarize.
David
mailto:sxdjd@ts.sois.alaska.edu
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