[Bug 1561228] Re: dmevent can not open shared object file libdevmapper-event-lvm2snapshot.so leads to lvcreate/lvremove being slow

[Launchpad Bug Tracker]

This bug was fixed in the package lvm2 - 2.02.133-1ubuntu10

---------------
lvm2 (2.02.133-1ubuntu10) xenial; urgency=medium

  * Cherry-pick change from lvm2 2.02.133-2 in Debian to move event plugins
    back onto the main library patch, which fixes problems with monitoring
    failing for snapshots and raid volumes.  Closes: #807279, LP: #1556451,
    LP: #1561228.

 -- Steve Langasek <steve.langasek at ubuntu.com>  Sat, 16 Apr 2016
00:06:53 -0700

** Changed in: lvm2 (Ubuntu)
       Status: New => Fix Released

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to lvm2 in Ubuntu.
https://bugs.launchpad.net/bugs/1561228

Title:
  dmevent can not open shared object file libdevmapper-event-
  lvm2snapshot.so leads to lvcreate/lvremove being slow

Status in lvm2 package in Ubuntu:
  Fix Released

Bug description:
  1) lsb_release -rd
  Description:	Ubuntu Xenial Xerus (development branch)
  Release:	16.04

  2) apt-cache policy lvm2
  lvm2:
    Installed: 2.02.133-1ubuntu7
    Candidate: 2.02.133-1ubuntu7
    Version table:
   *** 2.02.133-1ubuntu7 500
          500 http://ports.ubuntu.com/ubuntu-ports xenial/main ppc64el Packages
          100 /var/lib/dpkg/status

  3) Expected lvcreate/lvremove test to take less than a second
  4) It took about 30 seconds instead

  
  To reproduce
  ============

  Use the script.

    export GROUP='group-test'
    export VOLUME='volume-test'
    export SNAPSHOT='_snapshot-test'
    export BACKING_FILE=/root/lvmbacking

    if ! vgs -o name | grep $GROUP; then
      dd if=/dev/zero of=$BACKING_FILE bs=1M count=2000
      losetup /dev/loop100 $BACKING_FILE
      pvcreate /dev/loop100
      vgcreate $GROUP /dev/loop100
    fi

    lvcreate -n $VOLUME $GROUP -L 1g
    lvcreate --name $SNAPSHOT --snapshot $GROUP/$VOLUME -L 1.00g
    lvremove -f $GROUP/$SNAPSHOT
    time lvremove -f $GROUP/$VOLUME

  
  During lvcreate/lvremove, /var/log/syslog would show:
  Mar 23 15:39:59 xenial-server-2016-01-18-ppc64el dmeventd[2753]: dmeventd libdevmapper-event-lvm2snapshot.so dlopen failed: libdevmapper-event-lvm2snapshot.so: cannot open shared object file: No such file or directory.

  
  Workaround
  ==========

  In /etc/lvm/lvm.conf, change snapshot_library to use absolute path:

    snapshot_library = "/lib/powerpc64le-linux-gnu/device-mapper
  /libdevmapper-event-lvm2snapshot.so"

  The workaround is obviously would only work for the specific architecture.  A
  proper fix would be to find out why dmevent can not load the library, and fix
  that.

  Additional Notes
  ================

  I have also tested this on Xenial x86 VM, and on baremetal install of Xenial.
  Had the same problem on both.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/lvm2/+bug/1561228/+subscriptions