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
