Check this out.... http://www-1.ibm.com/servers/aix/whitepapers/db_perf_aix.pdf
Charlie Hurtubise Tecsys Inc. -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] Behalf Of Thach, Kevin G Sent: Wednesday, June 30, 2004 1:44 PM To: [EMAIL PROTECTED] Subject: Re: raw partitions If possible, I would be interested in obtaining a copy of the pdf document you refer to. Thanks! -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Stef Coene Sent: Wednesday, June 30, 2004 12:52 PM To: [EMAIL PROTECTED] Subject: Re: raw partitions On Tuesday 29 June 2004 20:33, [EMAIL PROTECTED] wrote: > ==> In article <[EMAIL PROTECTED]>, Joni > Moyer <[EMAIL PROTECTED]> writes: > > Hello all! > > > > I was reading the performance tuning guide and it states that we > > should use raw partitions for server db, log and disk storage pool > > volumes for an AIX server and I was just wondering if this is true > > and what the benefits are of configuring volumes in this manner? > > Simpler, faster, less space overhead. Euh, yes and no. For AIX and jfs2 file systems, you can enable CIO (in /etc/filesystems: "options = rw,cio"). If you do so, your file systems are as fast as raw devices. So you have the benefits of a file system and the speed of a raw device. The I/O requests are directly done on the disk, all cache is skipped. I have a pdf file about this setup for oracle and the speed you can get. We once enabled this on a very busy AIX server and the oracle database was very, very fast. > > As I understand it, if we configure raw logical volumes, the AIX > > volume group will need to be applied to a raw logical volume, as > > opposed to a standard UNIX filesytem. For each disk and logical volume, there is a /dev/r* device that you can use. This is the raw device version of the normal /dev/* device. Stef -- [EMAIL PROTECTED] "Using Linux as bandwidth manager" http://www.docum.org/