From mzito@gridapp.com Wed, 02 Jul 2003 10:59:12 -0700 From: "Matthew Zito" Date: Wed, 02 Jul 2003 10:59:12 -0700 Subject: RE: Filesystem for Linux production database server? Message-ID: MIME-Version: 1.0 Content-Type: text/plain Reiserfs' biggest strength is in its ability to deal with directories with huge numbers of files in a very speedy fashion. Obviously, for oracle this is less relevant. As far as the max-readahead option, I don't understand the specific relevance to fibre-attached storage. I would imagine, though admittedly I no longer have large storage arrays to play with, that setting readahead to be higher could damage performance against arrays with "intelligent" caching algorithms. Having the OS handle read-ahead rather than the array will likely fool the array into thinking that the i/o patterns are more sequential than they are. This will cause them to pre-allocate cache regions and pre-fetch more tracks off disk, which could adversely impact performance. Totally separate from that, Redhat strongly advises _against_ tuning that parameter. I happen to be doing I/O testing right now anyway, so maybe I'll gen up some workloads on different filesystems and go nuts. Thanks, Matt -- Matthew Zito GridApp Systems Email: [EMAIL PROTECTED] Cell: 646-220-3551 Phone: 212-358-8211 x 359 http://www.gridapp.com > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of Craig I. Hagan > Sent: Wednesday, July 02, 2003 4:11 AM > To: Multiple recipients of list ORACLE-L > Subject: Re: Filesystem for Linux production database server? > > > > Linux file systems usually do not support direct I/O (bypassing the > > buffer cache), which means that you're going to have double caching > > with almost > > This is no longer the case. Look at the O_DIRECT open option, > which can be used with oracle. Make sure that your > distribution has support for it. > > One other thing: if you are using fibre attached storage and > are *not* using async io, then put some usefully large value > into /proc/sys/vm/max-readahead, remember it is power of 2 > minus one, so youd want to look at values like 255, 511, and 1023. > > > > As for availability, you'll have to go with some RAID > controller and > > standby > > database or RAC. In case of RAC, your choice of file > systems is clear (OCFS). > > Whatever you do, do not configure your RAID as RAID-5 but > RAID 1+0 (BARF). > > what he said, save that i like raid10. > > HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Matthew Zito INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).