[Asterisk-Users] Re: load balancing 20 asterisk servers

[Rich Adamson]

> How about a management server that polls the asterisk servers every 
> minute with snmp to check cpu and ram cache, maybe even drive space.  
> Then you could have a script decide whether the server can handle 
> anymore connections.

There are lots of different ways to measure how busy a server happens
to be and snmp can be made to do that. Another is simply counting
pkts/sec to/from a server.

> I am still a beginner so I am not sure how you could have asterisk 
> delegate calls to other servers.
> would a redirect transfer remove the management server from the loop?

Part of the problem is that something needs to detect a failed server
and that failure can be anything from a broken cat5 cable to an
internal s/w error (* failed, OS is up), etc.
 
> using loadbalancer?
> http://www.vovida.org/applications/downloads/loadbalancer/

The person that wrote that has a rather lengthy list of ToDo's and
hasn't touched it since May 2002. I'd bet they decide the problem was
much larger then what they initially thought. Documenting and
handling the exception conditions with sip & rtp is more difficult
then what it appears on the surface.
 
> these are just ideas I am tossing out here for you.

Writing code to handle asterisk-to-asterisk load balancing would be
substantially easier then dealing with sip phones and adapters that
have hard coded logic, and in at least some cases, that logic is
less then robust.

All sip devices would need to be covered one way or another.