At Fri, 15 Jul 2005 14:53:26 -0700, Jeffrey W. Baker wrote: > > On Fri, 2005-07-15 at 15:29 -0600, Ron Wills wrote: > > Here's a bit of a dump of the system that should be useful. > > > > Processors x2: > > > > vendor_id : AuthenticAMD > > cpu family : 6 > > model : 8 > > model name : AMD Athlon(tm) MP 2400+ > > stepping : 1 > > cpu MHz : 2000.474 > > cache size : 256 KB > > > > MemTotal: 903804 kB > > > > Mandrake 10.0 Linux kernel 2.6.3-19mdk > > > > The raid controller, which is using the hardware raid configuration: > > > > 3ware 9000 Storage Controller device driver for Linux v2.26.02.001. > > scsi0 : 3ware 9000 Storage Controller > > 3w-9xxx: scsi0: Found a 3ware 9000 Storage Controller at 0xe8020000, IRQ: > > 17. > > 3w-9xxx: scsi0: Firmware FE9X 2.02.00.011, BIOS BE9X 2.02.01.037, Ports: 4. > > Vendor: 3ware Model: Logical Disk 00 Rev: 1.00 > > Type: Direct-Access ANSI SCSI revision: 00 > > SCSI device sda: 624955392 512-byte hdwr sectors (319977 MB) > > SCSI device sda: drive cache: write back, no read (daft) > > > > This is also on a 3.6 reiser filesystem. > > > > Here's the iostat for 10mins every 10secs. I've removed the stats from > > the idle drives to reduce the size of this email. > > > > Linux 2.6.3-19mdksmp (photo_server) 07/15/2005 > > > > avg-cpu: %user %nice %sys %iowait %idle > > 2.85 1.53 2.15 39.52 53.95 > > > > Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn > > sda 82.49 4501.73 188.38 1818836580 76110154 > > > > avg-cpu: %user %nice %sys %iowait %idle > > 0.30 0.00 1.00 96.30 2.40 > > > > Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn > > sda 87.80 6159.20 340.00 61592 3400 > > These I/O numbers are not so horrible, really. 100% iowait is not > necessarily a symptom of misconfiguration. It just means you are disk > limited. With a database 20 times larger than main memory, this is no > surprise. > > If I had to speculate about the best way to improve your performance, I > would say: > > 1a) Get a better RAID controller. The 3ware hardware RAID5 is very bad. > 1b) Get more disks. > 2) Get a (much) newer kernel. > 3) Try XFS or JFS. Reiser3 has never looked good in my pgbench runs
Not good news :(. I can't change the hardware, hopefully a kernel update and XFS of JFS will make an improvement. I was hoping for software raid (always has worked well), but the client didn't feel conforable with it :P. > By the way, are you experiencing bad application performance, or are you > just unhappy with the iostat figures? It's affecting the whole system. It is sending the load averages through the roof (from 4 to 12) and processes that would take only a few minutes starts going over an hour, until it clears up. Well, I guess I'll have to drum up some more programming magic... and I'm starting to run out of tricks... I love my job some day :$ > Regards, > jwb > ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
