Bug 707056

It's also a bit weird that it reports "No longer monitoring snapshot snapper-snap1
" since isn't it constantly monitoring that volume?

This is indeed a bit suspicious. I'll look into it.

I have two observations: 1) I cannot reproduce this issue with snapshots, but it *might* be timing-dependent. Does it happen every time?
2) A similar symptom happens with mirrors (the "No longer monitoring" messages are frequent, and annoying). The following patch fixes the situation for mirrors (and, I would expect, also with snapshots, since it applies to common code):

Index: daemons/dmeventd/plugins/lvm2/dmeventd_lvm.c
===================================================================
RCS file: /cvs/lvm2/LVM2/daemons/dmeventd/plugins/lvm2/dmeventd_lvm.c,v
retrieving revision 1.5                        
diff -u -p -r1.5 dmeventd_lvm.c                
--- daemons/dmeventd/plugins/lvm2/dmeventd_lvm.c        30 Sep 2010 11:40:14 -0000      1.5
+++ daemons/dmeventd/plugins/lvm2/dmeventd_lvm.c        29 Aug 2011 18:42:47 -0000
@@ -114,7 +114,7 @@ int dmeventd_lvm2_init(void)
                        goto out;
                }
                /* FIXME Temporary: move to dmeventd core */
-               lvm2_run(_lvm_handle, "_memlock_inc");
+               lvm2_run(_lvm_handle, "_dmeventd_enter");
        }
                                               
        _register_count++;                     
@@ -130,7 +130,7 @@ void dmeventd_lvm2_exit(void)
        pthread_mutex_lock(&_register_mutex);  
                                               
        if (!--_register_count) {              
-               lvm2_run(_lvm_handle, "_memlock_dec");
+               lvm2_run(_lvm_handle, "_dmeventd_leave");
                dm_pool_destroy(_mem_pool);    
                _mem_pool = NULL;              
                lvm2_exit(_lvm_handle);
 
Index: tools/lvmcmdlib.c
===================================================================
RCS file: /cvs/lvm2/LVM2/tools/lvmcmdlib.c,v
retrieving revision 1.12
diff -u -p -r1.12 lvmcmdlib.c
--- tools/lvmcmdlib.c   5 Mar 2010 14:48:34 -0000       1.12
+++ tools/lvmcmdlib.c   29 Aug 2011 18:42:57 -0000
@@ -81,9 +81,12 @@ int lvm2_run(void *handle, const char *c
 
        /* FIXME Temporary - move to libdevmapper */
        ret = ECMD_PROCESSED;
-       if (!strcmp(cmdline, "_memlock_inc"))
+       if (!strcmp(cmdline, "_dmeventd_enter")) {
                memlock_inc_daemon(cmd);
-       else if (!strcmp(cmdline, "_memlock_dec"))
+                init_dmeventd_monitor(DMEVENTD_MONITOR_IGNORE);
+       } else if (!strcmp(cmdline, "_memlock_inc"))
+               memlock_inc_daemon(cmd);
+       else if (!strcmp(cmdline, "_memlock_dec") || !strcmp(cmdline, "_dmeventd_leave"))
                memlock_dec_daemon(cmd);
        else    
                ret = lvm_run_command(cmd, argc, argv);

New patch is waiting for review, see http://www.redhat.com/archives/lvm-devel/2011-October/msg00058.html

Fixed in lvm2-2.02.88-2.el5.

"Extension of snapshot $snap finished successfully" messages are no longer
reported at all, even when threshold is turned on. Marking verified.

Nov 17 16:16:08 hayes-01 lvm[7344]: Monitoring snapshot snapper-auto_extension 
Nov 17 16:16:18 hayes-01 lvm[7344]: Extending logical volume auto_extension to
120.00 MB
Nov 17 16:16:18 hayes-01 lvm[7344]: Logical volume auto_extension successfully
resized
Nov 17 16:23:33 hayes-01 lvm[7344]: No longer monitoring snapshot
snapper-auto_extension 
Nov 17 16:25:02 hayes-01 lvm[7344]: Monitoring snapshot snapper-auto_extension 
Nov 17 16:25:12 hayes-01 lvm[7344]: Extending logical volume auto_extension to
120.00 MB
Nov 17 16:25:12 hayes-01 lvm[7344]: Logical volume auto_extension successfully
resized
Nov 17 16:25:20 hayes-01 lvm[7344]: No longer monitoring snapshot
snapper-auto_extension 


2.6.18-274.el5

lvm2-2.02.88-4.el5    BUILT: Wed Nov 16 09:40:55 CST 2011
lvm2-cluster-2.02.88-4.el5    BUILT: Wed Nov 16 09:46:51 CST 2011
device-mapper-1.02.67-2.el5    BUILT: Mon Oct 17 08:31:56 CDT 2011
device-mapper-event-1.02.67-2.el5    BUILT: Mon Oct 17 08:31:56 CDT 2011
cmirror-1.1.39-10.el5    BUILT: Wed Sep  8 16:32:05 CDT 2010
kmod-cmirror-0.1.22-3.el5    BUILT: Tue Dec 22 13:39:47 CST 2009

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Automatic snapshot resize now doesn't report redundant information to syslog after successful operation.

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-2012-0161.html