FW: external_command_buffer_slots??

[Ryan Bowlby]

----- Original Message ----
From: "Wheeler, Jonathan (STFC,RAL,ESC)" <jonathan.wheeler at stfc.ac.uk>
To: nagios-users at lists.sourceforge.net
Sent: Thursday, August 20, 2009 12:20:30 AM
Subject: [Nagios-users] FW:  external_command_buffer_slots??

> -----Original Message-----
> From: Ryan Bowlby [mailto:rbowlby83 at yahoo.com]
> Sent: 20 August 2009 00:57
> 
> Hello everyone,
> 
>  I joined the list just for this!
> 
> A google search of "external_command_buffer_slots" doesn't provide
much
> beyond the official documentation. Can someone please clarify for me
what
> this directive is actually doing.
> 
> Is this buffer internal to Nagios?
> The name seems unfortunate because it reminds me of the external
command
> file which obviously can't be increased beyond 4096 without hacking
fifo
> sizes in kernel source.
> 
> What downside is there to setting this buffer to say.. 8192 or <?
> 
> Can someone describe where in the chain of events check results reside
in
> this buffer?

We make use of this directive and the corresponding
"check_result_buffer_slots".  As I understand it these refer to internal
buffers used by the Nagios process to store commands and results after
they have been read from the pipe file but before they are processed.
This allows other high priority tasks to take precedence if required.
For example, we currently use Nagios 2 with NDOutils and the code that
passes results to the corresponding ndo2db daemon is in a
single-threaded part of the code; if there is a delay in this operation
(say caused by heavy load on the MySQL server), the Nagios process is
held up until the delay has cleared.  I use
external_command_buffer_slots=40960 and check_result_buffer_slots=61440;
you can see how many of these slots have been used in the current Nagios
process if you run program nagiostats.  What you are doing is allowing
the Nagios process to get more memory for these buffers if required;
assuming that your server has plenty of memory, you should have no
problem if you increase the value of these directives.

Jonathan Wheeler 
e-Science Centre 
Rutherford Appleton Laboratory
-- 





Thanks that is exactly what I needed to know!
It would seem it's doing fine but I will increase it two fold just in case. Below is the corresponding nagiostats line:

Used/High/Total Command Buffers:        0 / 2889 / 4096

I always thought this was referring to the external command file. :(


      

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