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<div class="moz-cite-prefix">Have you done the math for the network
connections? BTF and external<br>
What bit rates for the sound?<br>
What codecs?<br>
How are calls coming in - SIP - analogue<br>
<br>
Disks OK(low IO per second)? Caching working OK?<br>
<br>
CPU may not be the problem if your CPU utilization is really that
low.<br>
<br>
Ron<br>
<br>
On 02/03/2015 10:26 AM, Mordechay Kaganer wrote:<br>
</div>
<blockquote
cite="mid:CA+xOVSM-bwV47GUsnaRNa10oPVC9XxDXx6ya2rNrVboknwq70Q@mail.gmail.com"
type="cite">
<div dir="ltr">B.H.
<div><br>
</div>
<div>Hello, all :-)</div>
<div><br>
</div>
<div>We have a cluster of Asterisk (v. 11.9) servers that host
IVR applications. The servers work behind SIP proxy (kamailio)
for load balancing.</div>
<div><br>
</div>
<div>All servers are in 2 processor configuration, 8-10 cores
per CPU.</div>
<div><br>
</div>
<div>When a particular server gets about 500 concurrent calls,
the sound quality begins to degrade, the sound plays slowly
and with clicks. As far as i understand, it's because asterisk
is unable to send the voice stream in time i.e. the server is
overloaded.</div>
<div><br>
</div>
<div>What i don't understand is, at the time that the server
appears to be overloaded and the audio quality is bad, actual
server's load is no more than 30-40% (60-70% idle CPU on
average). IMHO, this indicates that for some reason the server
is unable to use it's CPU capacity efficiently. May be because
of some kind of thread contention inside asterisk?</div>
<div><br>
</div>
<div>I have read blogs that advice to divide physical server
into several VMs and they claim that this will improve the
total capacity. In my own experience, this did not work very
well and seems like the visualization actually made the
quality worse.</div>
<div><br>
</div>
<div>Do you have any advice for me (other than purchasing more
servers ;-) ?</div>
<div><br>
</div>
<div>Thanks!</div>
<div>
<div><br>
</div>
-- <br>
<div class="gmail_signature">
<div dir="ltr">
<div style="direction:rtl"><span
style="color:rgb(102,102,102)">משיח NOW!</span><br>
</div>
<font color="#666666">Moshiach is coming very soon,
prepare yourself!</font>
<div dir="rtl"><font color="#666666">יחי אדוננו מורינו
ורבינו מלך המשיח לעולם ועד!</font></div>
</div>
</div>
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<br>
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<br>
<pre class="moz-signature" cols="72">--
Ron Wheeler
President
Artifact Software Inc
email: <a class="moz-txt-link-abbreviated" href="mailto:rwheeler@artifact-software.com">rwheeler@artifact-software.com</a>
skype: ronaldmwheeler
phone: 866-970-2435, ext 102</pre>
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