Error message when creating LVM snapshot

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux Server 5 - x86_64

Issue

  • While creating LVM snapshot with the command syntax lvcreate -L${SIZE} -s -n ${LV\_SNAP\_NAME} ${LV_NAME}, the following error gets logged
${VG_NAME}-${LV_SNAP_NAME}: event registration failed: 5991:3 libdevmapper-event-lvm2snapshot.so dlopen failed: /usr/lib64/liblvm2cmd.so.2.02: undefined symbol: dm_list_empty
  vg/snapshot0: snapshot segment monitoring function failed.
  Logical volume "${LV_SNAP_NAME}" created

Resolution

  • The error which gets logged on the lvm snapshot creation is harmless. This happens because the dmeventd-based snapshot usage monitoring is not currently enabled for this snapshot.

  • The dmeventd process needs to be killed, so that it will restart next time and poll/activate all the lvm snapshots. Activating the monitoring for a snapshot would prevent this from happening.

  • You can also reboot the system after lvm2 package update.

Root Cause

The problem is that If the daemon has been running before the package update (daemon is not restarted) it will still use the old binary/library images. Killing and re-starting it will force it to use the newly updated versions

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