[asterisk-users] Could Asterisk be crashing under high context switches?

[Jason Martin]

Hello! 

I have been struggling with Asterisk 1.6 and DAHDI for the past few weeks. We are an outgoing call center with 30 internal analog phones hooked up to 2 Rhino CB24 channel banks. The banks are connected to a Rhino R4T1 card in a Dell 2950 server with 8 gigs of RAM. The 2 other ports on the R4T1 go to our 2 PRIs.

In this configuration, we have trouble maintaining stability. It may be fine for days, but soon the load slowly creeps up on the server from below 1 all the way up to 6 which is when no one can dial out and asterisk pretty much has to be killed to be stopped.

We also have bandwidth.com set up as a SIP provider. If we use bandwidth.com, stability is greatly improved.

I installed munin on the phone server yesterday and noticed something dramatic, I think! Asterisk became unstable 3 times yesterday. 2 of those times, the number of context switches went to almost 80k the first time, then over 70k the second. 

First question - is this abnormal for around 20 ongoing recorded calls?

I did a little bit of searching and found this:
http://wiki.sangoma.com/files/wanpipe-linux-asterisk-tutorials/How_to_Reduce_Asterisk_System_Loads.pdf

It talks about zaptel/DAHDI chunk size and that directly affects system load.

Second question - the document explains how to change the chunk size for Sangoma hardware. Is there a general way to do that for DAHDI?

Thanks is advance!

Jason Martin
Metrix Matrix, Inc.
785 Elmgrove Rd, Bldg 1
Rochester, NY 14624
Office: 888-865-0065 x202
Mobile: 585-705-1400