FW: NDO Utils Question

[Christopher McAtackney]

2009/6/25 Wheeler, JF (Jonathan) <jonathan.wheeler at stfc.ac.uk>:
>> -----Original Message-----
>> From: Christopher McAtackney [mailto:cristoir at gmail.com]
>> Sent: 25 June 2009 14:51
>>
>> Hi everyone,
>>
>> I have a quick question about Nagios and NDOUtils I was hoping someone
>> could answer.
>>
>> What happens if the database that NDO Utils is using becomes
>> unavailable? (e.g. the server has crashed).
>
> The answer depends a lot on whether you are using Nagios v2 or Nagios
> v3; we are using Nagios v2.11.  My understanding is that in Nagios v2,
> the code that communicates with the event broker module in
> single-threaded.  Therefore a problem with the SQL server can jam up
> Nagios to the extent that it effectively stops running commands.  In
> Nagios v3, threading has been rewritten and this problem no longer
> exists.

Sorry, should have specified that. I'm running 3.0.6.

>> I'm assuming Nagios will continue to monitor and send notifications as
>> normal, is this correct?
>
> In Nagios v2 it seems that almost all activity is suspended when you are
> using NDOutils and the MySQL server is unavailable; this continues until
> the SQL server is restored.  One solution is to restart Nagios without
> the broker_module.
>
>> What about the service check results that would normally be passed to
>> NDO Utils and then stored in the database? Are they queued somewhere?
>> And if so, how is the capacity of this queue defined? If they are not
>> queued, what happens? Will NDO Utils just throw an error for each
>> result it tries to store in the database and fails? Will this affect
>> the core Nagios process?
>
> Results passing into the command pipe are stored.  The relevant
> parameters are in nagios.cfg; they are external_command_buffer_slots and
> check_result_buffer_slots - by default these are set to 4096 (see
> documentation within the configuration file).

Great, that's what I was hoping for. Do you have any experience of
setting this buffer to much higher values? Not that I necessarily
intend to, but it's always useful to know the effects of pushing the
system to its limits.

>> Hopefully someone can provide some insight.
>
> Hopefully this has

Yes, this has been very helpful, thanks for your answer. Thanks as
well Carsten, much appreciated.


> Jonathan Wheeler
> e-Science Centre
> Rutherford Appleton Laboratory

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