On Jul 25, 2005 at 12:07, Michael Ulitskiy mdu113@acedsl.com wrote:
On Monday 25 July 2005 08:21 am, Jan Janak wrote:
No, you don't need hundreds of children, usualy 16 is maximu what you need. Newer ser versions contain connection pool, so each child will open exactly one database connection and it will be reused across modules.
What about processing that involves slow DNS queries? I thought this would eat up available workers quite quickly and further processing will be blocked? Please correct me if I'm wrong.
You can install local (running on the same host as the proxy) DNS cache that can also cache negative entries (those that do not exist or cannot be looked up), such as dnsmasq. This way the slow query would be performed once and subsequent queries will be answered from the cache. Moreover, kernel maintains a queue of incoming SIP requests and it will continue receiving SIP messages even if all processes are blocked. The kernel starts to drop incoming SIP messages once the queue is full.
Well, I guess it's not a solution. It's a workaround at best. I'd vote for something apache-like. I.e. master process monitoring the number of idle children and forking additional as needed. Thanks anyway.
Why not start them all from the beginning? Is not like they will eat a lot of resources...
Also could you (or someone) give me a rough estimation on what is the optimal number of children to serve let's say 10k sip clients as registrar and proxy with moderately complex config file, but not involving DNS queries? INVITEs may involve several database queries to a dedicated database server. I understand that the question is rather vague, I'm just interested in a rough estimation and some real-world numbers people use.
Try it and if you can see packets in the socket buffers (netstat) increase the number of children. I would use 20-50 children. The "lots of db connections" problem is solved when using connection pools (or by increasing the maximum connections in mysql's config :-)). You could use also tune the dns timeout (limit the maximum time a dns request can take). For this you would need either unstable (grep NEWS for dns_) or to edit your /etc/resolv.conf and set the timeout and attempts options and remove the search or domain lines.
Andrei