[JDEV] JPOLLD

[Vijay Kumar]

RE: [JDEV] jabber users limit !!-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

well jpolld is used to increse the no of simulatanous users ,as by
default sytem support only 1024 TCP connection only at a time
so this means that only 1024 users can connect at a time ,so we use
jpolld ,it act as layer between user & jabberd
all the TCP coonections first connected to the machine where jpolld
is running ,then jpolld say take 100's of connections
& multiplex them to jabberd on a single socket .

extract from the README file of jpolld 
REASONING
- ---------
The need for large IO channels is one of the primary problems that
surrounds any network based server once it starts to reach a high
number of users. For Jabber the primary IO strain comes from the
large number of persistant sockets that are necessary to have a
largely scaled server. As the number of sockets devoted to a single
program increases it becomes extremely difficult for a program to
keep track and iterate over the sockets to get and process the
information. The functions used to iterate over the sockets can also
have possible limitations on the number of sockets it can handle. The
most obvious solution (as it is in most IO problems) is to remove the
IO from the actual data processing. In Jabber this is what we have
jpolld for.
[... Is there any more? ...]
THEORY
- ------
The jpolld will act as a TCP multiplexer, it accepts multiple
connections from clients and connects back to the server with only
one connection. All of the client connections are then translated
between the single server socket. This setup allows for multiple
jpollds to be run on seperate front end boxes, and connect back to a
larger central server.
[... I'll put more in here ...]
SETUP
- -----
The first consideration to setting up a large Jabber system is the
target max simultaneous user count. You then need to figure out how
many of those users you want a single jabberd server to handle. A
good rough estimate is 40,000-60,000 users handled by a single
jabberd. Next you need to evaluate the network requirements, and how
the TCP handling boxes will be designed. The amount of sockets that a
single box can handle is mostly tied to the number of NICs and the
number of CPUs from the system (as per the model this box is mainly
piping the IO and doing a very low amount of processing). Finding a
balance between these two elements is crucial, if you are piping
information to the jabberd server too quickly then it will become
backed up and be very hard for it to recover, if it is too slow and
the other side too beastly, potential cost goals will be wasted on
overlypowerful servers.
THe jabberd server must have a seperate configuration section for
each of the jpollds that will be connecting to it. The configuriation
is done by adding an accept service to the jabberd configuration, an
example:
<service id='jpolld'>
<host>jpolld.127.0.0.1</host>
<accept>
<ip/>
<port>5225</port>
<secret>test</secret>
</accept>
</service>
Each of the jpollds must have a seperate port setting and seperate id
setting.
The jpolld is controlled by command line options. The two required
options for jpolld are -n and -s, which are the name and secret
respectively. These must match the id and secret from the
configuration that is done to jabberd. The other options to the
jpolld are also important and summarized here:
- -d The remote port if it is different than 5225 as set in the jabberd
config
- -l The local port that the jpolld will listen on, defaults to 5222
- -h The IP of the machine to connect to with jpolld, this will default
to 
localhost.
When the two are connected together fully all resulting interaction
should be transparent to the users.
[... Clean this up! ...]
- ----- Original Message ----- 
From: Edward J Becker 
To: jdev at jabber.org 
Sent: Friday, December 08, 2000 11:09 PM
Subject: [JDEV] JPOLLD


 
 What is Jpolld where can I get more info on it?
 
Edward
 

-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 6.5.8 for non-commercial use <http://www.pgp.com>

iQA/AwUBOjQmEPMOJs9j9QjTEQJrZACfYKpqSAifG5DwJouas+8BBwanFdcAoM1U
tIiNYoAMrsEyFNXOsMSpCT18
=5eRL
-----END PGP SIGNATURE-----