[Bug 613619] [NEW] qem/kvm misinterprets LVM volume geometry

[Hadmut Danisch]

Public bug reported:

Binary package hint: qemu-kvm

Hi,

when running qemu/kvm with kvm logical volumes as virtual disks, there's
a severe problem, maybe with disk geometry.

When partitioning the lvm volume with fdisk or parted, generating the
partition device entries with kpartx, creating filesystems (ext3,
fat16,..) and installing a linux with debootstrap, there's quite often
the problem that the virtual machine then has problems accessing the
virtual disk, resulting in read errors (usually misinterpreting dos
filesystems, beeing unable to mount or fsck an ext3 and so on).

Looks like the same problem as reported on http://qemu-
forum.ipi.fi/viewtopic.php?f=4&t=5218

Sometimes the problem did not occur when I use fdisk in dos compatibilty
mode and/or rebooting the host after creating the partition table.

Maybe that's a problem of disk geometry. Linux does not maintain a disk
geometry for LVM volumes, so most tools like partition and filesystem
generation tools use a default geometry of 255 heads and 63 sectors. On
the other hand, the -drive option of qemu/kvm does not accept this
geometry. The number of heads seems to be limited to 16. This is a
severe problem since it can crash virtual machines and destroy data.

regards

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: qemu (not installed)
ProcVersionSignature: Ubuntu 2.6.32-24.38-generic 2.6.32.15+drm33.5
Uname: Linux 2.6.32-24-generic i686
Architecture: i386
Date: Wed Aug  4 22:21:59 2010
KvmCmdLine: Error: command ['ps', '-C', 'kvm', '-F'] failed with exit code 1: UID        PID  PPID  C    SZ   RSS PSR STIME TTY          TIME CMD
MachineType: TOSHIBA Satellite L300
ProcCmdLine: BOOT_IMAGE=/vmlinuz-2.6.32-24-generic root=/dev/mapper/nord-root ro quiet splash
ProcEnviron:
 PATH=(custom, user)
 LANG=de_DE.utf8
 SHELL=/bin/tcsh
SourcePackage: qemu-kvm
dmi.bios.date: 03/19/2008
dmi.bios.vendor: INSYDE
dmi.bios.version: 1.30
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Base Board Product Name
dmi.board.vendor: Intel Corp.
dmi.board.version: Base Board Version
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 1
dmi.chassis.vendor: Chassis Manufacturer
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnINSYDE:bvr1.30:bd03/19/2008:svnTOSHIBA:pnSatelliteL300:pvrPSLB0E-02T01XGR:rvnIntelCorp.:rnBaseBoardProductName:rvrBaseBoardVersion:cvnChassisManufacturer:ct1:cvrChassisVersion:
dmi.product.name: Satellite L300
dmi.product.version: PSLB0E-02T01XGR
dmi.sys.vendor: TOSHIBA

** Affects: qemu-kvm (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386 lucid

-- 
qem/kvm misinterprets LVM volume geometry
https://bugs.launchpad.net/bugs/613619
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