Il 31/08/2012 15:19, Andrew Holway ha scritto: > I have 4096 block devices from sda..sdx. Do you mean (here and in your other cache=none message) that the host devices have 4k logical blocks? If so, and if you use cache=none, you need to export them as 4k block devices to the guest as well. This is done with the "logical_block_size=4096" sub-option in the "-device virtio-blk-pci" command-line option. Libvirt however does not support this yet. Alternatively, there were QEMU-side patches to support emulating a 512-over-4k device (using read-modify-write). One version I posted is at http://lists.gnu.org/archive/html/qemu-devel/2011-12/msg01570.html -- I need to rebase and repost. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html