topic Optimal Parameters For JFS in Disk Enclosures

Optimal Parameters For JFS

George Nikoloudis_1 — Tue, 20 Nov 2001 16:42:51 GMT

Dear All
What are the optimal parameters for the JFS configuration in order an ORACLE DB OLTP and DSS system to operate?
Is there any way where the already defined parameters to changed?

Thanks a lot

Re: Optimal Parameters For JFS

A. Clay Stephenson — Tue, 20 Nov 2001 18:33:44 GMT

Hi:

Here are the vxfs mount options I've found to be best for Oracle:

For Datafiles and Indices:
-o rw,suid,convosync=direct,mincache=direct,delaylog,nodatainlog

For archive logs and redo logs:
-o rw,suid,delaylog,nodatainlog

The convosync=direct,mincache=direct bypass the UNIX buffers - the performance is almost exactly the same as raw disk. If you use this option, you should reduce the UNIX buffer cache and use the memory to increase the SGA buffers.

I also find that turning off dynamic buffer cache by setting bufpages to a non-zero value
performs better. It is almost always pointless to exceed bufpages=80000 (320MB and this is very generous). If this is a pure Oracle server then bufpages=25600 (100MB is plenty).

Re: Optimal Parameters For JFS

Alan Riggs — Tue, 20 Nov 2001 22:09:47 GMT

To add to Clay's list, use the dsync setting for rollback and temp files:

delaylog,mincache=dsync,convosync=dsync,nodatainlog

Re: Optimal Parameters For JFS

Bill Hassell — Wed, 21 Nov 2001 02:28:50 GMT

Just a note in case you don't dfind these options in the man pages: they are part of Advanced JFS. Anyone running Oracle or other filesystem-based database should also have a copy of Advanced JFS (also known as Online JFS).