[Xymon] Technical questions regarding message flow

[Michael Beatty]

I have some technical questions in regard to how the actual message flow 
between server / clients take place.

The first questions relate to network traffic.  My intent is to monitor 
a large number of clients (getting close to 9,000) so this is going to 
be a question I need to fully understand before I go too far. What does 
the message look like and how big is it (excluding message text) ?  Is 
it XML?  How is the connection made between the client and host?  Are 
sockets made? How does the server handle large volumes of connections.  
One thing I have read is that any bottle necks will be more likely with 
disk I/O than network traffic, is this fair?

Secondly, what is the process of message flow between client and 
server?  I understand how the xymonclient is configured to run at a 
defined interval (configured in clientlaunch.cfg), it gathers data from 
its logs and sends the data to the server.  The server saves this in its 
/data/hist path along with any rrd data.  The server uses this data to 
display its web pages. The next part I'm not sure I understand 
correctly.... The sever then sends a response to the client that 
contains data that instructs the client what information it wants next 
time (this is taken from hosts.cfg?)  The client then uses this response 
to determine which information to collect and send the next time the 
client is launched.   So, aside from the server's ping test, all traffic 
is initiated by the client?

Thank you for any help.

-- 
Michael Beatty