[Serusers] Server dimensioning

[inge]

Hi Miklos,

Be largely thanks for your detailed reply.

I will find a way to study one-up on a plateform of pre production.

My configuration is quite heavy (several thousand lines). However,
access to databases are relatively efficient.

Regards,

Adrien

Le jeudi 25 juin 2009 à 10:00 +0200, Miklos Tirpak a écrit :
> Hi,
> 
> I think in most of the cases it is worth increasing the number of child 
> processes. A child process is blocked during the SIP msg processing, and 
> if there is any problem the blocking can take a lot of time, for example 
> the processes can be blocked because of a not responding DNS server. 
> When this happens SER cannot handle new incoming messages if there is no 
> more child process available. Btw, even if there is still a child 
> process available, if the new msg requires a DNS query again then there 
> is not too much difference. But if the new msg is routed without being 
> blocked again then it will be successfully handled by SER while the 
> other messages are waiting for the response of the DNS server. (I think 
> it is also worth setting the timeout of the DNS query (and other 
> external queries) to a low value.)
> And it is always good to increase the the number of processes when the 
> limit is not the CPU but SER waits for some external source too much, 
> for example lots of database queries to another server. -- SER can start 
> processing the new messages at least while the previous ones are still 
> waiting for the database result.
> 
> The memory usage is not increased too much by the number of processes 
> because of the copy-on-write strategy of the OS. The number of file 
> descriptors needed is increased, and each child process keeps a separate 
> DB connection to the server. So you may have to increase the limits. 
> Also keep in mind that when the number of processes is too high and they 
> simultaneously try to access some shared resource that involves locking 
> then the risk of contention is also high.
> 
> So in general, it is better to test it by yourself because the 
> performance heavily depends on your configuration and the servers SER 
> tries to access during the msg routing. Include the failure cases in 
> your tests to find the optimum number of processes.
> 
> Regards,
> Miklos
> 
> On 06/24/2009 02:45 PM, inge wrote:
> > Hi all,
> > 
> > I wonder about the "child" parameter in ser.cfg.
> > 
> > What's the average processing capacity (number of requets/process) ?
> > 
> > Currently, the parameter is set to 4, the default value. What's the risk
> > of the increase ?
> > 
> > SER runs on RedHat AS4 with Intel Xeon Quad 3.0 Ghz.
> > 
> > Thanks for your support.
> > 
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