RE: Tru64 Direct I/O

Thanks, Stephen

I'll pass this along to our SA's. We will be migrating to the Compaq SAN; upgrading our controllers to fiber (HSG80's ?) but we have 2 older 8400's as production primary & failover, and yes, they both have access to the same disk farm, though not concurrently (currently).

-----Original Message-----
Sent: Thursday, January 09, 2003 5:06 PM To: ORACLE-L_at_fatcity.com

Mike,

Compaq SAN and Tru64 and direct I/O have been nothing but trouble in my recent experience. I put in over 35 hours over Christmas and last weekend working on recoveries of system crashes. Our problem appears to have been relating to the fact that several machines had mount points on disks that were striped and accessed from different machines. According to vendor techs, this shouldn't be a problem, but told us to move all mount points around so that there were no "splits" where a disk was being used from more than one host. So far, we have not had a crash since we did that (uptime of 4 days -- a new record for the past 2-3 months). We've disabled direct I/O, but I don't know whether or not this was part of the problem. Our problems started getting worse after going to 5.1a and got severe when we started using multiple nodes of our cluster. Compaq said for awhile that the problem was with the GS160 so we bought 4 ES45's. Talk about a sales pitch "Our big machine we sold you 12 months ago stinks, you should 'upgrade' to a bunch of our smaller ones."

Good luck.

Stephen

>>> HANDM_at_polaroid.com 01/09/03 01:54PM >>>
OK, everything I've read so far on using Direct I/O with an Oracle database
says it's a bad idea. Either performance problems or block corruption may
occur. The notes on metalink (132391.1) refer to Tru64 5.0A and 5.1 but not
5.1A (to which we've recently upgraded). So is anyone using Direct I/O on
Tru64 successfully.  

Oracle V8.1.7.3 EE (non-OPS)
Tru64 5.1A on Alpha Servers  

Mike Hand
Polaroid Corp

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Author: Hand, Michael T
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