I had this issue again this morning, tis is the log from zensyslog, it looks like that at 09:34 it just stops and starts again after 12:34.
See corresponding graphs below.
2013-04-09 09:29:43,142 INFO zen.maintenance: Performing periodic maintenance
2013-04-09 09:29:43,143 INFO zen.zensyslog: Counter eventCount, value 626766
2013-04-09 09:29:43,144 INFO zen.zensyslog: 157 devices processed (0 datapoints)
2013-04-09 09:29:43,146 INFO zen.collector.scheduler: Tasks: 159 Successful_Runs: 266 Failed_Runs: 0 Missed_Runs: 0 Queued_Tasks: 0 Running_Tasks: 0
2013-04-09 09:34:43,164 INFO zen.maintenance: Performing periodic maintenance
2013-04-09 09:34:43,164 INFO zen.zensyslog: Counter eventCount, value 626782
2013-04-09 09:34:43,166 INFO zen.zensyslog: 157 devices processed (0 datapoints)
2013-04-09 09:34:43,168 INFO zen.collector.scheduler: Tasks: 159 Successful_Runs: 294 Failed_Runs: 0 Missed_Runs: 0 Queued_Tasks: 0 Running_Tasks: 0
2013-04-09 09:39:43,183 INFO zen.maintenance: Performing periodic maintenance
2013-04-09 09:39:43,183 INFO zen.zensyslog: Counter eventCount, value 626799
2013-04-09 09:39:43,184 INFO zen.zensyslog: 157 devices processed (0 datapoints)
2013-04-09 09:39:43,186 INFO zen.collector.scheduler: Tasks: 159 Successful_Runs: 311 Failed_Runs: 0 Missed_Runs: 0 Queued_Tasks: 0 Running_Tasks: 0
2013-04-09 12:28:48,143 INFO zen.zensyslog: 0 events processed in 0.00 seconds
2013-04-09 12:28:48,182 INFO zen.zensyslog: Deleting PID file /opt/zenoss/var/zensyslog-localhost.pid ...
2013-04-09 12:28:48,182 INFO zen.zensyslog: Daemon SyslogDaemon shutting down
2013-04-09 12:31:31,304 INFO zen.zensyslog: Connecting to localhost:8789
2013-04-09 12:31:35,524 INFO zen.zensyslog: Connected to ZenHub
2013-04-09 12:31:35,547 INFO zen.maintenance: Performing periodic maintenance
2013-04-09 12:31:35,547 INFO zen.zensyslog: Counter eventCount, value 626800
2013-04-09 12:31:35,555 INFO zen.zensyslog: 0 devices processed (0 datapoints)
2013-04-09 12:31:35,555 INFO zen.collector.scheduler: Tasks: 1 Successful_Runs: 0 Failed_Runs: 0 Missed_Runs: 0 Queued_Tasks: 0 Running_Tasks: 0
2013-04-09 12:32:09,414 INFO zen.zensyslog: Connecting to localhost:8789
2013-04-09 12:32:09,429 INFO zen.zensyslog: Connected to ZenHub
2013-04-09 12:32:09,444 INFO zen.maintenance: Performing periodic maintenance
2013-04-09 12:32:09,444 INFO zen.zensyslog: Counter eventCount, value 626801
2013-04-09 12:32:09,445 INFO zen.zensyslog: 0 devices processed (0 datapoints)
2013-04-09 12:32:09,445 INFO zen.collector.scheduler: Tasks: 1 Successful_Runs: 0 Failed_Runs: 0 Missed_Runs: 0 Queued_Tasks: 0 Running_Tasks: 0
2013-04-09 12:37:25,780 INFO zen.maintenance: Performing periodic maintenance
2013-04-09 12:37:25,780 INFO zen.zensyslog: Counter eventCount, value 626816
2013-04-09 12:37:25,781 INFO zen.zensyslog: 22 devices processed (0 datapoints)
2013-04-09 12:37:25,782 INFO zen.collector.scheduler: Tasks: 24 Successful_Runs: 2 Failed_Runs: 0 Missed_Runs: 0 Queued_Tasks: 0 Running_Tasks: 0
2013-04-09 12:42:25,865 INFO zen.maintenance: Performing periodic maintenance
2013-04-09 12:42:25,866 INFO zen.zensyslog: Counter eventCount, value 626833
2013-04-09 12:42:25,867 INFO zen.zensyslog: 34 devices processed (0 datapoints)
I am busy removing the sending of syslog messages to zenoss from all devices, maybe that helps.
Warm regards,
Wayne