Alleviating Nagios i/o contention problem

[Frost, Mark {PBC}]

Greetings, listers,

We've got an on-going issue with i/o contention.  There's the obvious problem that we've got a whole lot of things all writing to the same partition.  In this case, there's just one big chunk of RAID 5 disk on a single controller so I don't believe that making more partitions is going to help.

On this same partition we have:

1) Nagios 3.2.1 running as the central/reporting server for a couple of other Nagios nodes that are sending check results via NSCA.  Approximately 6-7K checks.

2) pnp4nagios 0.6.2 (with rrd 1.4.2) writing graph data.

There's a 2nd server configured identically to the first that's acting as a "hot spare" so it also receives check data from the 2 distributed nodes and writes its own copy of the graph data locally as well.

At the moment I'm concerned about the graphdata, but because I can only see i/o utilization as an aggregate, I can't tell what is the worst component on that filesystem -- status.dat updates?  graph data?  writes to the var/spool directory?  We also look at continued growth so this is only going to get worse.

These systems are quite lightly loaded from a CPU (2 dual-core CPUs) and memory (4GB) perspective, but the i/o to the nagios filesystem is queuing now.

We're about to order new hardware for these servers and I want to make a reasonable choice.  I'd like to make some reasonable changes without requiring too exotic of a setup.  I believe these servers are currently Dell 2950s and they're all running Suse Linux 10.3 SP2.

My first thought was to potentially move the graphs to a NAS share which would shift that i/o to the network.  I don't know how that would work though and it would ultimately be an experiment.

What experiences do people out there have handling this kind of i/o and what have you done to ease it?


Thanks very much!

Mark

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://www.monitoring-lists.org/archive/users/attachments/20100925/eec3be45/attachment.html>
-------------- next part --------------
------------------------------------------------------------------------------
Start uncovering the many advantages of virtual appliances
and start using them to simplify application deployment and
accelerate your shift to cloud computing.
http://p.sf.net/sfu/novell-sfdev2dev
-------------- next part --------------
_______________________________________________
Nagios-users mailing list
Nagios-users at 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