On Fri, Jul 22, 2011 at 2:44 PM, Victor Stinner <victor.stinner@xxxxxxxxxxxxx> wrote: > Hi, > > I have a new fast computer to run many virtual machines. Everything looks > very fast, except the installation of new operating systems in KVM. The > installation is very fast until it begins to write on disk. It looks like it > writes slower and slower. I tried Debian, FreeBSD, OpenIndiana and OpenBSD: > same problem. The FreeBSD installer displays the speed: it starts at 780 > KB/sec (which it already very slow) to finish between 1 and 8 KB/sec. ) is the host FS btrfs? ) are virtio modules in the initramfs (or kernel probably)? ) are you sure virtio is being used (eg. are the disks called vdX vs sdX)? ) is the disk bus set to virtio (virtmanager)? ) is the disk's cache mode set to none [or maybe writeback] (virtmanager)? ) is the disk's storage format set to "raw", should be (virtmanager)? ) is caching enabled on the image? () probably need to change the cache mode on the disk, or if the host is btrfs you need to flag the image with whetever is needed to prevent continuous COWing. C Anthony -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
