Subject: Re: disk speed query
To: Manuel Bouyer <email@example.com>
From: Patrick Welche <firstname.lastname@example.org>
Date: 05/11/2005 14:05:51
On Wed, May 11, 2005 at 02:39:58PM +0200, Manuel Bouyer wrote:
> On Wed, May 11, 2005 at 12:46:19PM +0100, Patrick Welche wrote:
> > Disks: sd0 sd1 cd0 cd1 sd2
> > %busy 100
> So the disk is 100% busy, it's really a disk or driver issue.
> > 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
65536000 bytes transferred in 15.417 secs (4250891 bytes/sec)
so the same roughly 4MB/s
> 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
Indeed.. not yet anyway..