> load average is a time averaged thing and in the case of a > 'thundering herd' problem you will see the LA spike up and > come down again over time. > > Do you see any problem as a result of this? Or is it just curiosity? > > you might want to use KTR or ktrace with scheduling events if you > really want to see the reason for this. It could just be a sampling > error when some 'tick' coincides with the sampling.. > > I have not seen any noticeable performance degradation when the LA spikes like this, and the main nuisance of this was Sendmail's behaviour. I have since set the options "RefuseLA=0" and "QueueLA=0" to avoid long stretches of SMTP being unavailable while the load averaged itself out.
At this point it is really just a nagging feeling that something is misbehaving and it's going to bite me when I least expect it (it always does!), so I would like to try and track down the source of the problems, but I'm not even sure where to begin looking. I have run some ktrace on sendmail and dovecot, but did not see anything that stood out, although I don't really know if I would recognize the problem in a kdump anyway (Too much information!) I'm not at all familiar with KTR, however. Is this something that can be run on a production host or should it be isolated to a dev box? I have cloned the jail into a dev environment on identical hardware, but only see the issue under production. I'm not sure if this is a factor of insufficient load or just not enough random strangeness outside of production. Any suggestions for how KTR might help pin this down or what to look for? _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-performance To unsubscribe, send any mail to "[email protected]"
