Oracle-L: RE: Veritas Quick I/O for Oracle

From: Nick Wagner <Nick.Wagner_at_quest.com>
Date: Wed, 26 Mar 2003 15:29:21 -0800
Message-ID: <F001.00573D44.20030326152921@fatcity.com>

Just be careful using the convosync=delay and convosync=closesync options. We have seen this corrupt redo log records.

Nick
-----Original Message-----
Sent: Wednesday, March 26, 2003 2:09 PM
To: Multiple recipients of list ORACLE-L

Dennis,

The benefits of QIO are realized not only by Oracle but also by the storage administrators. Oracle improvements come from kernelized async I/O, elimination of UNIX double-buffering and single-writer file header locking in the O/S. Storage administrators gain from managing a cooked file system. It enables many online tasks (like provisioning for new storage on active file systems, restriping on the fly, wholesale relocation of databases) that are impossible or very painful and error prone with raw partitions. My group has a good relationship with UNIX SAs and we try help whenever we can.

However, it ain't a no-brainer. In pre-ODM environments QIO files have to be pre-created on the UNIX side before being added to the database, or the file offlined and enabled for QIO after the fact. It's a simple command line tool but it takes planning and preparation plus adjustments to existing procedures. Our biggest point of pain is during recoveries. In the thick of things we keep forgetting to pre-create the QIO files before restoring datafiles to an alternate location. The recoveries are successful but we pay a performance penalty until we negotiate downtime to QIO-enable the recovered files (which is really renaming the data file and creating a link with a specific pattern that triggers the code path for QIO handling.)

As for the speed claims coming from your salesperson, all I can say is that we get pretty close to raw speeds. I highly recommend it especially for online redo logs, and it's easy to revert to regular files if you change your mind.

HTH
Tony Aponte

-----Original Message-----
<mailto:DWILLIAMS_at_LIFETOUCH.COM> ]
Sent: Friday, March 14, 2003 11:14 AM
To: Multiple recipients of list ORACLE-L

Is anyone using Veritas Quick I/O for Oracle? We are purchasing some new Solaris systems with fiber channel and Veritas File System, and the Veritas salesperson is claiming "up to 400 times faster". I would like to know if anyone else has discovered this miracle and what benefits you are seeing. Thanks.
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Author: Nick Wagner
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