Red Hat Bugzilla – Bug 702410
lvremove of snapshot produces multipathd "uevent trigger error"
Last modified: 2012-02-21 01:34:46 EST
Description of problem: Customer reported a backup application that periodically removes snapshots results in multipathd sending "uevent trigger error" messages. I investigated this, and will attach my results. Net-net: this is multipathd processing uevents from LVM. If possible, multipathd should filter out and not process LVM events, or better error messages should be given. Version-Release number of selected component (if applicable): RHEL5.3: device-mapper-multipath-0.4.7-23.el5-x86_64 How reproducible: Somewhat hard to reproduce - probably related to timing of LVM / multipathd uevent handling.
Created attachment 497132 [details] Analysis of messages, based on device-mapper-multipath source
Created attachment 497133 [details] Messages file, trimmed for 500 lines before / after "uevent trigger error" This is a trimmed version of the messages file from the system. Full information on the system, including a sosreport and messages file, can be obtained from the case.
I've kept multipathd from printing an error in this case.
Tried 1000 times for these two scripts, no luck to reproduce on RHEL 5.7 GA (device-mapper-multipath-0.4.7-46.el5) for LVM: === for X in `seq 1 1000`;do lvcreate -n tmp_test -L 4M VolGroup00 service multipathd start sleep 1 lvremove /dev/mapper/VolGroup00-tmp_test -f sleep 1 service multipathd stop if [ "$(grep "uevent trigger error" /var/log/messages)CHK" != "CHK" ];then grep "uevent trigger error" /var/log/messages break fi done ==== for dm ==== for X in `seq 1 1000`;do echo "0 1024000 zero" | dmsetup create zero_test_dm ls /dev/mapper/ service multipathd start sleep 1 dmsetup remove zero_test_dm ls /dev/mapper/ sleep 1 service multipathd stop if [ "$(grep "uevent trigger error" /var/log/messages)CHK" != "CHK" ];then grep "uevent trigger error" /var/log/messages break fi done ==== Patch has been applied into a tar file. no way for me code review. I also tried above commands on new package: device-mapper-multipath-0.4.7-48.el5, no uevent error message found. SanityOnly.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2012-0166.html