Re: Huge Cricket Installations

On Tue, Nov 21, 2006 at 12:34:27PM -0000, Dermot Williams wrote:
> I?ve a Cricket install (1.0.5) that polls over XXXX nodes.
> Obviously this is too many for a single box to poll, so I?ve spread
> the load over three machines. The actual Cricket installation is
> in a directory on a NetApp NAS that is mounted on each machine over
> NFS. This in itself is problematic because of locking problems and
> so on but for the most part it works pretty well and facilitates
> a quick turn-around in the event that a machine needs to be replaced.

A few things come to mind:

* are you using the Net-SNMP library instead of the default Cricket SNMP
library?  That will dramatically improve the speed of your collector.
See cricket/lib/snmp.pm and cricket/lib/alternate/snmpUtils.pm

* you can avoid locking problems by keeping the Cricket installation
on local storage in each box, and then copying the files to the NFS
directory after the collector is finished.  I use that strategy now,
but I don't know if it will scale properly for your environment.  If
the file copies run in the "dead time" after collection is done but
before the next collector runs, it won't be a problem (though from your
description I wonder if you have any "dead time" between runs at all).

* Not clear to me if you're trying to compile the entire Cricket tree
on the individual collector machines - you only need to compile on that
machine the part that it is actually collecting.  The host that does the
displaying (you do have another host to do that, right?) can have a
different compile with all the subtrees - as long as you keep the sources
synched properly, it should work.  Also, you don't have to compile the
Cricket tree for the collector hosts on the collector hosts - if
you have another machine with an identical architecture, build it there
and copy config.db over.

* Use rsync for the file copies when playing games with config.db or
moving RRD files back and forth, since it guarantees that there won't
be a partial or stale version of the file present during the copy.

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