disk i/o performance problem
Hi, I'm trying to track down a pretty apparent problem that I'm
having with disk i/o on an Etch box. Basically, I have two identical
machines. One is running Etch and one is running CentOS. The Etch
machine is really slow. I'm trying to figure out why. Details are
as follows:
Etch: (output of hdparm)
/dev/sda:
Timing cached reads: 1588 MB in 2.00 seconds = 794.41 MB/sec
Timing buffered disk reads: 176 MB in 3.03 seconds = 58.15 MB/sec
/dev/sda:
IO_support = 0 (default 16-bit)
readonly = 0 (off)
readahead = 256 (on)
geometry = 30401/255/63, sectors = 488397168, start = 0
Linux etch 2.6.18-4-k7 #1 SMP Wed May 9 23:42:01 UTC 2007 i686 GNU/
Linux
CentOS: (output of hdparm)
/dev/sda:
Timing cached reads: 4480 MB in 2.00 seconds = 2242.86 MB/sec
Timing buffered disk reads: 176 MB in 3.03 seconds = 58.16 MB/sec
/dev/sda:
IO_support = 0 (default 16-bit)
readonly = 0 (off)
readahead = 256 (on)
geometry = 30401/255/63, sectors = 488397168, start = 0
Linux centos 2.6.18-8.1.3.el5PAE #1 SMP Mon Apr 30 20:26:37 EDT 2007
i686 athlon i386 GNU/Linux
Please note that I'm specifically not trying to spark a centos/debian
war here. I just provide the CentOS numbers because it's the same
hardware and there's a pretty obvious difference between the two
otherwise identical machines.
I'm not sure where to look next. The fact that the hdparm settings
are identical indicate that the problem (or setting?) may be
elsewhere. But where?
Does anybody have an idea of where to look?
phil.
--
Whirlycott
Philip Jacob
phil@whirlycott.com
http://www.whirlycott.com/phil/
Reply to: