Hi,
On Tue, 2006-05-23 at 11:54 +0100, Stephen C. Tweedie wrote:
On Mon, 2006-05-22 at 20:26 -0700, Ben wrote:
> Today I upgraded to the new xen and kernel packages that just came
> out, as I'd been looking forward to all the IO cleanup supposedly in
> xen 3.0.2. Imagine my disappointment when I found out that my domU's
> virtual disks still seem to be throttled at around 2MB/s sustain
> writes for some reason. My dom0 is "much" better at ~14MB/s sustained
> writes.
Are you using a file or device-backed virtual device?
On two local guests on a rawhide box:
Device-backed guest (LVM on fast SATA disk):
dom0 hdparm -t: 53.70 MB/sec
domU hdparm -t: 53.61 MB/sec
File-backed guest:
dom0 hdparm -t: 85.7138 MB/sec
domU hdparm -t: 75.2901 MB/sec
(The file is a sparse file that's only about 50% full, so there's
actually less data being read in that case.)
The file-backed domain definitely takes a lot more dom0 CPU time to
serve, but they are both pretty fast.
Cheers,
Stephen