Re: SNMP Query Optimisation Suggestions

Kerry Milestone <[email protected]>
Newsgroups gmane.network.cacti.user
Organization Sanger Institute
Message-ID <[email protected]>
Hello there,

this is perhaps something that the project should maybe look at, as an
additional option to throttle snmp queries for particular hosts.

We have a multitude of switches/routers that we poll.  They are modern, some
stacked with hundreds of ports and in some cases the management CPU is dual core.

However, the switches and routers are designed such that almost all compute is
done on FPGA chips as close to the physical port as possible - and obviously
very good for networking performance.

The functions that are left over, are done on the main CPU.  One such function
is of course SNMP.

We have a couple of monitoring systems and cacti which all use SNMP.  As with
Robert, I have seen the CPU hit 100% which times out queries.  Investigation
pointed to the SNMP process on the switch and mitigation was to stagger the
crons on the various monitoring tools from overlapping.


I do like the shear volume of queries that can be sent with cacti in a single
go, and the threaded polling on cacti is rather good.


As a workaround, it could be possible I guess to use SNMPd in a proxy format and
fire this off through something like twistedsnmp
(http://twistedsnmp.sourceforge.net/) for throttling but I suspect that trying
to buffer UDP will cause more trouble than it's worth.


Regards,
Kerry.





On 14/05/12 22:35, Gandalf wrote:
> I'm not aware of any throttling mechanism. In fact, we try to fire as many
> requests as possible against our targets to be able to poll more items within a
> given time. Sp, personally, I'm not aware of any workaround
> Reinhard
-- 
--------------------------------------
.- Kerry Milestone                  -.
.- Principle Network Engineer       -.
.- Wellcome Trust Sanger Institute  -.
--------------------------------------


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