What kernel are you running. If your running 2.6.x use the deadline scheduler or downgrade to 2.4.23aavm 2.6.[0-9] has major problems with the IO scheduler since the process scheduler is very fast now.
DVP ---- Dathan Vance Pattishall http://www.friendster.com > -----Original Message----- > From: Kevin Burton [mailto:[EMAIL PROTECTED] > Sent: Friday, May 06, 2005 1:58 PM > To: mysql@lists.mysql.com > Subject: MySQL not using optimum disk throughput. > > > We have a few of DBs which aren't using disk IO to optimum capacity. > > They're running at a load of 1.5 or so with a high workload > of pending queries. > > When I do iostat I'm not noticing much IO : > > Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s > wkB/s > avgrq-sz avgqu-sz await svctm %util > sda 0.00 13.73 128.43 252.94 1027.45 1695.10 513.73 > 847.55 7.14 90.13 285.00 2.53 96.57 > > .... > > This is only seeing about 500k -> 1M per second throughput. > > When I run bonnie++ on these drives they're showing 20M->40M > throughput. > > Which is really strange. > > Most of our queries are single INSERTS/DELETES. I could > probably rewrite these to become batch operations but I think > I'd still end up seeing the above iostat results but with > higher throughput. > > .... so I'd like to get to the bottom of this before moving forward? > > I ran OPTIMIZE TABLE on all tables but nothing. > > The boxes aren't paging. > > They're running on a RAID5 disk on XFS. > > Could it be that the disks are having to do a number of HEAD > seeks since we have large tables? > > -- > > > Use Rojo (RSS/Atom aggregator)! - visit http://rojo.com. > See irc.freenode.net #rojo if you want to chat. > > Rojo is Hiring! - http://www.rojonetworks.com/JobsAtRojo.html > > Kevin A. Burton, Location - San Francisco, CA > AIM/YIM - sfburtonator, Web - http://peerfear.org/ GPG > fingerprint: 5FB2 F3E2 760E 70A8 6174 D393 E84D 8D04 99F1 4412 > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
