We're using Nagios 3.2.3 for simulation of monitoring load in a load test environment as well as for monitoring production services. I've notices some interesting behavior in the way Nagios schedules checks when checks are inhibited either though the CGI Process Commands or by setting a check_period timeperiod that inhibits checks during regularly scheduled down times.
Normally Nagios seems to spread out host and service checks evenly over time but when checks are stopped with the Process Command, Nagios seems to reschedule checks so that they are "bunched up" much closer together. This creates alternating periods of densely scheduled and more sparsely scheduled checks that seem to persist when checks are turned on again. It has a noticeable effect in our load testing. The only way--or the quickest way--to get Nagios to smooth out the schedule again is to stop the process completely until all the scheduled check times have passed. In testing Nagios monitoring of our production services, if I use the check_period to inhibit checks during our down times, I notice that as the downtime approaches, ALL checks are rescheduled for the exact time that the downtime ends (according to the check_period). This creates a big spike in monitoring activity after the downtime. One way to avoid this, I think, is to let checks run during the down times but inhibit notifications instead by using the timeperiod to define a notification_period. But I wonder if this "bunching" up of the schedule when using check_periods is ever a desirable behavior. These aren't critical issues for us since we can work around them procedurally. But I wonder if there his a way to prevent the scheduled checks from getting bunched together like this if/when you need to inhibit checks for a time while keeping Nagios running. Maybe the auto_rescheduling options in the nagios.cfg are meant to address this, but they have a potentially negative effect on performance according to the comments around them in the file. ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev _______________________________________________ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
