Passive check reception in nagios-1.2 does not scale (has anyone already written a patch?)

[michael at optusnet.com.au]

Bjørnar Bjørgum Larsen <bjornar.bjorgum.larsen at ementor.no> writes:
> Hello,
> 
> there seems to be no way of getting nagios-1.2 to process passive service checks faster than once per second. In our tests, setting 
> command_check_interval=-1
> produces far worse results than setting 
> command_check_interval=1s
> 

> Problem: If the above is generally true, given an average command
> length put into the external command file of 120 characters, and a
> FIFO length of 4096 characters, it's impossible for nagios-1.2 to
> handle more than 35 passive checks a second. We want our
> passive-only nagios-1.2 hosts to process at least 100 checks a
> second, and we don't see any other reasons why a nagios host doing
> nothing but receiving and forwarding checks can't do that.

Indeed. If you look through the list archives, you'll see a patch
from David Parrish or myself that addresses that (search for 'hash').

Note that just checking more often is disasterous. For some
very odd reason, nagios accepts the passive check result,
and then forks to give it back again to the main
process!!

The solution is to check very frequently (so as to empty
the FIFO), but only process them once per second.

See the patch for the details.

Michael.


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