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[eduardo at ypytecnolog...]

people 


I have a running Asterisk 1.8.28 in great Dell server with two xeon processors and 16gb of ram and HD SAS 15k (Raid 1). This server is recording all calls (placed to record the audio in a ram disk), the entire CDR goes straight to MySQL by cdr_mysql.so. Each call runs some validation and AGI's have an auto dialer system that generates calls over the manager. Calls originate and terminate via SIP (no transcode). 


With this structure, even being a great server, we can not spend 150 simultaneous calls. When it reaches 140, the load average goes up a lot and the calls start to get very bad audio, tear, etc.. Using the top we see that all the processing is for asterisk. In this scenario, I think there is some limitation in Asterisk, or even the manager due to the auto dialer. 


Can anyone give me any tips where I can look where is the bottleneck? I need to get at least 250 calls that server quality.


tks

[sgriepentrog at digium...]

Your bottleneck is most likely your drive bandwidth.  Even with SAS drives, you'll need to move to a raid 5+ solution with 6+ drives to continue to increase the concurrent calls, or use a storage appliance.


To confirm this, install the tool nmon and use the v and d options to bring up the resource usage indicators and drive busy/throughput statistics.





On Wed, Jul 23, 2014 at 2:48 PM, Eduardo Leones <eduardo@ypytecnologia.com.br (eduardo@ypytecnologia.com.br)> wrote:

[rwheeler at artifact-s...]

I would also do some math on the bandwidth requirement.

If you divide your disk bandwidth by your recording bit rate what is the theoretical maximum number of calls that you can record at once? Assumes that you have infinite CPU and memory and that you can actually drive the disks at their maximum.
If this comes out to 300, you are already there. If it comes out to 3000, you have something wrong in your setup or your assumptions and a target to work towards.

What quality are you using in the recording? 44k per second(CD quality sound) uses a lot more bandwidth than 3K (telephone quality)
What encoding are you using?
How low a bit rate can you use and still have usable recordings? If they are for legal or audit use, you can go pretty low. If you are recording soundtracks for reuse in training or publication, you may require higher bit rates.

If you disable recording, how many simultaneous calls can you support? Just to be sure that recording is the issue.

Ron

On 23/07/2014 4:29 PM, Scott Griepentrog wrote:

[eduardo at ypytecnolog...]

Thanks for the feedback. 


In this case SSD disks you think it solves?



Eduardo


2014-07-23 18:01 GMT-03:00 Ron Wheeler <rwheeler@artifact-software.com (rwheeler@artifact-software.com)>:

[eduardo at ypytecnolog...]

Thanks for the feedback. 


In this case SSD disks you think it solves?





2014-07-23 17:29 GMT-03:00 Scott Griepentrog <sgriepentrog@digium.com (sgriepentrog@digium.com)>:

[rwheeler at artifact-s...]

Do the calculations for both and see what the answer is.
The nice thing about having a model is that you can test configurations without actually having to build one until you are confident that it should work.

Ron


On 23/07/2014 5:04 PM, Eduardo Leones wrote:

[asterisk.org at sedwar...]

Please don't top-post.

On Wed, 23 Jul 2014, Eduardo Leones wrote:

[asterisk at lists.mino...]

On 23/7/14 10:29 pm, Steve Edwards wrote:

[asterisk.org at sedwar...]

On Wed, 23 Jul 2014, Chris Bagnall wrote:

[sgriepentrog at digium...]

Whether SSD drives allow you to add any additional calls depends entirely on whether or not they can be written to faster than the SAS drives you have.  My experience shows SSD's can be twice as fast as run-of-the-mill SATA, but the performance difference compared to SAS is likely not as great, and could even be worse.  You'll need to test two drives to find out.  I recommend mounting both to test them and copying a very large ISO file using dd which will give you the transfer rate when finished.  Then you should have your answer.



On Wed, Jul 23, 2014 at 4:03 PM, Eduardo Leones <eduardo@ypytecnologia.com.br (eduardo@ypytecnologia.com.br)> wrote:

[eduardo at ypytecnolog...]

Thank you all for the answers. I will do tests to find the problem. 


One other question I have, in the scenario that I sent, how bad would be to transcode G711 to G729 in 70% of calls? There is a study that shows a statistically loss of performance (concurrent calls) with active transcode?


tks





2014-07-24 8:54 GMT-03:00 Scott Griepentrog <sgriepentrog@digium.com (sgriepentrog@digium.com)>:

[eduardo at ypytecnolog...]

Another question, what audio format I use in MixMonitor to maintain a connection with reasonable quality and reduce the use of I / O disk? Today I use wav.

tks



2014-07-24 9:05 GMT-03:00 Eduardo Leones <eduardo@ypytecnologia.com.br (eduardo@ypytecnologia.com.br)>:

[asterisk.org at sedwar...]

Please don't top-post.

Please trim irrelevant posts.

On Thu, 24 Jul 2014, Eduardo Leones wrote: