Subject: Re: disk speed query
To: Patrick Welche <email@example.com>
From: Manuel Bouyer <firstname.lastname@example.org>
Date: 05/11/2005 14:39:58
On Wed, May 11, 2005 at 12:46:19PM +0100, Patrick Welche wrote:
> pic0 pin 10 9 cow
> Disks: sd0 sd1 cd0 cd1 sd2 pic0 pin 5 64 fmin
> seeks pic0 pin 14 85 ftarg
> xfers 73 pic0 pin 15 143501 itarg
> bytes 4221K 100 pic0 pin 0 1028 wired
> %busy 100 1068 pdfre
So the disk is 100% busy, it's really a disk or driver issue.
> (the load of 4 is basically: dnetc, cat, ioflush, aiodoned)
> so it really isn't doing anything else...
> (csh built-in time)
> % time cat olddata03_04m > /dev/null
> 0.0u 10.1s 13:25.74 1.2% 0+0k 208+1io 0pf+0w
> % ls -l olddata03_04m
> -rw-r--r-- 1 postgres postgres 3465758203 May 10 18:48 olddata03_04m
> % ls -lh olddata03_04m
> -rw-r--r-- 1 postgres postgres 3.2G May 10 18:48 olddata03_04m
> 3.2G/13:25 wall time = 4.1G, so "progress" seems to be correct...
> 3GHz P4, 2GB ram. A complication, is that sd2 is really 2 disks plugged into
> to the lsilogic raid controller, combining them (striping?), and presenting
> as a singe drive to the OS:
Hum. Can you try a dd on the raw device, and see what speed we get from
a sequential read ?
dd if=/dev/rsd2d of=/dev/null bs=64k count=1000
The next test would be to benchmark each disk individually on the same
controller, to see if it's an issue with the mpt driver, or the raid
stuff in the controller itself. But if the system is in use this may not be
Manuel Bouyer <email@example.com>
NetBSD: 26 ans d'experience feront toujours la difference