SLES10SP4 certain LVM actions report device-mapper targets not detected in kernel

  • 7010069
  • 27-Jan-2012
  • 27-Apr-2012

Environment

SUSE Linux Enterprise Server 10 Service Pack 4

Situation

Using either pvmove or creating a snapshot on SLES10SP4 with lvm2-2.02.17-7.36.1 fails with e.g:

test64:~ # lvcreate -v -L 300M -s -n newsnapvol /dev/system/test
  Setting chunksize to 16 sectors.
  snapshot: Required device-mapper target(s) not detected in your kernel

Please see the additional information section for a successful run of creating a snapshot device.

Resolution

Please update to lvm2-2.02.17-7.38.3 or later.

Cause

The usual behavior of lvm2 command is to load the necessary module for the requested action automatically.  In case of creating a snapshot device this would be dm-snapshot or for pvmove it loads dm-mirror. The version of lvm2 in question does not load the required modules and thus the command fails.

On systems where the update cannot be installed immediately the interim solution is to load the modules manually using the modprobe command:
  • modprobe dm-snapshot
  • modprobe dm-mirror

Additional Information

Successful output of creating a snapshot device with SLES10SP4:

test64:~ # lvcreate -v -L 300M -s -n newsnapvol /dev/system/test
    Setting chunksize to 16 sectors.
    Executing: /sbin/modprobe dm-snapshot 
    Finding volume group "system"
    Archiving volume group "system" metadata (seqno 2).
    Creating logical volume newsnapvol
    Creating volume group backup "/etc/lvm/backup/system" (seqno 3).
    Found volume group "system"
    Creating system-newsnapvol
    Loading system-newsnapvol table
    Resuming system-newsnapvol (253:1)
    Clearing start of logical volume "newsnapvol"
    Found volume group "system"
    Found volume group "system"
    Creating system-test-real
    Loading system-test-real table
    Resuming  (253:2)
    Loading system-test table
    Creating system-newsnapvol-cow
    Loading system-newsnapvol-cow table
    Resuming  (253:3)
    Loading system-newsnapvol table
    Suspending system-test (253:0) with filesystem sync.
    Suspending system-test-real (253:2) with filesystem sync.
    Found volume group "system"
    Loading system-test-real table
    Suppressed system-test-real identical table reload.
    Resuming system-test-real (253:2)
    Loading system-newsnapvol-cow table
    Suppressed system-newsnapvol-cow identical table reload.
    Resuming system-newsnapvol (253:1)
    Resuming system-test (253:0)
    Creating volume group backup "/etc/lvm/backup/system" (seqno 4).
  Logical volume "newsnapvol" created
test64:~ #

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