[JDEV] Scale of server

[Jason Reineri]

I'm actually testing load on a server right now.  I have one box with
three instances of dpsm, one instance of jabberd, as well as the yahoo
and msn transports running.  The user information is stored in a mySQL
db running on the same machine and jabber accesses it through a version
of xdb_sql that we have modified to fix a few quirks and to make it work
with the msn transport.  The way we are load balancing the connections
to the three instances of dpsm is to just run each one on a virtual ip
and set up our dns to round robin the three ip's.
 
With a straight test that does nothing but connect sockets to the
server, we can get 10,000 connections per instance of dpsm.  Three
instances of dpsm seems to be the limit with this test, as there are
diminishing returns with any more than that.  I'm now using a tester app
I found in the CVS repository to get an actual load test.  The app has
some problems with it so we are tweaking it and running tests.  I don't
have solid numbers yet, but I know that I have had 3,000 users
simultaneously logged in and all of them sending messages.  The problem
with this test is that if you have 3,000 people logged in at any given
time, they will not be constantly talking to each other.  So with some
tweaking we are trying to make a load test that will more accurately
simulate a load.
 
What we are trying to accomplish here is to have 30,000 clients
connected to the one box, with a percentage of them talking that would
accurately reflect a real life server.
 
Note:  Our server machine is just a desktop that we stole to test on.
It's a one CPU P4 1.3Ghz I believe, with 1GB RAM.  If we had multiple
CPU's I suspect we could get away with running even more instances of
dpsm.  We are also going to try adding 2 more network cards to the
machine so each instance of dpsm will be on it's own network card.  Let
me know if you need any more info.  I've found the information on
scaling Jabber to be pretty lean and hard to find.
 
Jason Reineri
Northridge Systems, Inc.
 
-----Original Message-----
From: Michael F. March [mailto:march at indirect.com] 
Sent: Thursday, January 10, 2002 2:38 PM
To: jdev at jabber.org
Subject: Re: [JDEV] Scale of server
 
Do you know of a Jabber server that has had 3K users on at one time?
 
	----- Original Message ----- 
	From: Jason Reineri <mailto:jreineri at northridge.com>  
	To: jdev at jabber.org 
	Sent: Thursday, January 10, 2002 7:29 AM
	Subject: RE: [JDEV] Scale of server
	 
	Jabber can handle 3000 concurrent users with no problem.  The
only problem you will have is that the select() function in Linux is
hard coded to a certain number of sockets.  In kernel 2.4 that limit is
1024.  You can either recompile the kernel to allow more, or you can use
dpsm or jpolld as your socket manager.  These socket managers use the
poll() function instead of select() and are not subject to the limit.
You will however have to increase the number of file descriptors you can
have open per process.  This can be done in a startup script that calls
ulimit.
	 
	Jason Reineri
	Northridge Systems, Inc.
	 
	-----Original Message-----
	From: Rodrigo Roman [mailto:dedalo at ferengi.com.ar] 
	Sent: Wednesday, January 09, 2002 6:14 PM
	To: 'jdev at jabber.org'
	Subject: [JDEV] Scale of server
	 
	I'm planing an instalation of jabber server in a isp, we have
aprox 3000 concurrent users (i dont know wich porcentage will use our
messanger) our client base is 150k users.
	Wich is the best implementation for this numbers? 
	Is jabber prepared for this? 
	Are all the transports able to work in this client base? 
	Thanks for your help! 
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