topic Single Writer Lock and hp-ux in Operating System - HP-UX

Single Writer Lock and hp-ux

Tomoaki SUZUKI — Mon, 22 Dec 2003 22:08:53 GMT

Hi All,
I found a White paper about Single Writer Lock on Solaris.

http://www.solarisinternals.com/si/reading/oracle_fsperf.pdf

Does the issue affect hp-ux or not ?
Online-JFS(Direct I/O) or Veritas Quick I/O avoid the issue ?

I think the whitepaper explains general issue of Unix Filesystems(UFS,VxFS).

Best Regards,

Re: Single Writer Lock and hp-ux

Dietmar Konermann — Tue, 23 Dec 2003 03:39:49 GMT

I think, you would need the Veritas Quick I/O option to get around this issue. As far as I know, also VxFS with Direct I/O may be affected by single writer lock contention.

Best regards...
Dietmar.

Re: Single Writer Lock and hp-ux

zhuchao — Tue, 23 Dec 2003 06:48:36 GMT

moving to raw device you will solve this problem.

Re: Single Writer Lock and hp-ux

Tomoaki SUZUKI — Thu, 25 Dec 2003 12:19:36 GMT

Thanks for All,
I want to get a evidence that single writer lock affect to Oracle performance.
I have hp glance,this tool helps me for the purpose ?

I know raw volume is best for performance,but it's difficult to change now.

Regards,

Re: Single Writer Lock and hp-ux

zhuchao — Thu, 25 Dec 2003 22:46:08 GMT

Since you want to make modification, you must know why you modify it.
Is IO really the bottleneck of your database?If yes, then tune it, if not , why bother tune it?

Sun has Concurrent DIrect IO which solve the single write lock, and AIX has CIO also solved this problem.

Wonder whether HP will also have a release of such support.Since now HP by default used vxfs, I think Veritas will not release such a product which will compete with QuickIO.