[asterisk-users] RE: Scaling Asterisk: Dual-Core CPUs not yielding gains at high call volumes

[JR Richardson]

> > >   In fact, it seems that somewhere between 200 and 300 calls, the two
> > > servers start to exhibit similar idle times despite one of them having
> > > twice as many cores.

Do you get any errors at max call capacity about "too many open files"?  You
may try increasing your file descriptors.

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* FILE DESCRIPTORS

  Depending on the size of your system and your configuration,
Asterisk can consume a large number of file descriptors.  In UNIX,
file descriptors are used for more than just files on disk.  File
descriptors are also used for handling network communication
(e.g. SIP, IAX2, or H.323 calls) and hardware access (e.g. analog and
digital trunk hardware).  Asterisk accesses many on-disk files for
everything from configuration information to voicemail storage.

  Most systems limit the number of file descriptors that Asterisk can
have open at one time.  This can limit the number of simultaneous
calls that your system can handle.  For example, if the limit is set
at 1024 (a common default value) Asterisk can handle approximately 150
SIP calls simultaneously.  To change the number of file descriptors
follow the instructions for your system below:

== PAM-based Linux System ==

  If your system uses PAM (Pluggable Authentication Modules) edit
/etc/security/limits.conf.  Add these lines to the bottom of the file:

root            soft    nofile          4096
root            hard    nofile          8196
asterisk        soft    nofile          4096
asterisk        hard    nofile          8196

(adjust the numbers to taste).  You may need to reboot the system for
these changes to take effect.

== Generic UNIX System ==

  If there are no instructions specifically adapted to your system
above you can try adding the command "ulimit -n 8192" to the script
that starts Asterisk.


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 JR
 --
 JR Richardson
 Engineering for the Masses