Public bug reported: On the host machine, a disk is configured with 4k sector sizes: --- sudo fdisk /dev/sdd
Disk /dev/sdd: 4000.6 GB, 4000627818496 bytes 255 heads, 63 sectors/track, 60797 cylinders Units = cylinders of 16065 * 4096 = 65802240 bytes Sector size (logical/physical): 4096 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0xf8eabb69 --- ... and when fdisking the lvm parition, also reports properly: --- Disk /dev/VMsVG/mail: 21.0 GB, 20971520000 bytes 255 heads, 63 sectors/track, 318 cylinders Units = cylinders of 16065 * 4096 = 65802240 bytes Sector size (logical/physical): 4096 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x6a3bdb21 --- However, within a VM using the LVM parition as a raw disk, its fdisk reports a 512 block size: --- Disk /dev/vda: 21.0 GB, 20971520000 bytes 16 heads, 63 sectors/track, 5079 cylinders Units = cylinders of 1008 * 4096 = 4128768 bytes Sector size (logical/physical): 4096 bytes / 4096 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x915c306a using cache=none, which is established practice for best performance on raw devices, the host system repeatedly fails to write to the disk, due to it trying to write 512 byte sectors while the backing is 4096. ** Affects: qemu-kvm (Ubuntu) Importance: Undecided Status: New ** Tags: 4k kvm lvm qemu sector -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to qemu-kvm in Ubuntu. https://bugs.launchpad.net/bugs/802081 Title: qemu raw/nocache fails to operate on LVM partition with 4k sector size To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/802081/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs