Re: [torrus-devel] Design sketch: SNMP collector with persistentmapping

[Stanislav S. <ssi...@ya...>]

--- Sam Stickland <sam...@sp...> wrote:

> Am I right in thinking that the only reason ifIndex mapping takes such a
> long time is because the devices can take a long time to respond? As you
> state, parallelisation (threading) solves this.
> 
> With the new multi-threaded collector surely it is now practical to update
> the mappings every time a device is polled? It's simply an SNMP walk of
> .1.3.6.1.2.1.31.1.1.1.1.

with 50000 or more polled counters, retrieving ifTable that frequent makes 
absolutely no sense. And it will take up all CPU time on the server.

These mappings may usually change only when the router reboots. 
At any other time, there's no sence to update this information.
So, of we need to build a scalable platform for large networks,
we have to keep this information in a persistent storage. 
At big networks the initialization phase takes 30 to 60 minutes,
just to retrieve those interface mappings.