[Asterisk-Users] SUCCESS - 512 Simultaneous Calls with Digital Recording

[Matt Florell]

On 9/20/05, Matt Roth <mroth at imminc.com> wrote:
> 
> Patrick,
> 
> Thank you for your suggestions.
> 
> Our initial runs were recording directly to an NFS mount and they 
> experienced the same problems as recording to the local disk. In our final 
> setup, the copy will be done to an NFS mount as long as it exists, falling 
> back to local disk only when the NFS server is down.
> 
> The theory that we're running on is that any I/O bottlenecks (or network 
> latencies in the case of NFS) only matter when they are bound to a call in 
> progress. In that scenario, the bottleneck would introduce a latency in 
> Asterisk's handling of the RTP packets causing call degradation and drops. 
> By decoupling I/O from live calls and performing the copies (a very 
> lightweight operation) in a separate process, we hope to not affect 
> Asterisk's real-time handling of the RTP packets.
> 
> Because of limited access to the test equipment, we were only able to test 
> up to storing the digital recordings on a RAM disk. Please shoot holes in 
> this setup if you see any weaknesses. Better today than on our go-live date.
> 
> Thanks,
> 
> Matthew Roth
> InterMedia Marketing Solutions
> Software Engineer and Systems Developer


Hello,

I'm very interested in the specifics of your setup. 
How much space is on the RAM disk? 
What kind of RAM drive is it? 
What format are you recording to?
What codec are the SIP calls being placed over?

We've run into the "Avoided deadlock" recording issues several times when 
trying to do more than 50 concurrent recordings. Changing the 
ast_channel_lock loop from 10 to 20 has helped somewhat reduce the warnings 
and reduce audio gaps on the recordings, but what is really needed for more 
robust recording is a configurable recording buffer that wouldn't freak out 
if a 10ms delay occurs. 

Good luck and please keep us updated on your progress,

MATT---
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