[Spread-users] More Performance Issues/Questions

Mike Perik mikep at foxriver.com
Tue Dec 21 14:27:41 EST 2004


Ok,  I think I've found the problem.

In the spread.conf I had two machines.  The leader is always the first 
machine.  The leader is the one who holds onto the token and he'll hold onto 
the token for the Hurry_timeout.   Since the first machine in the 
configuration file is the client machine he holds onto it for Hurry_timeout 
seconds.  It goes into a select with the Hurry_timeout and since the 
server/publisher is waiting for the token to publish the client waits the 
whole time (Hurry_timeout or 2 seconds by default) since there is nothing to 
read.  I'm assuming the server queues  up all the messages that are being 
sent and when it gets the token it sends them all.  

I switched the order of the two machines in the configuration file around and 
the problem essentially went away.

If I'm correct on how this is working, I have a couple of questions?

What if I have two servers that are publishing data at a high rate and neither 
of them are the "leader"?
What kind of delay is this going to cause?  
If I have 20-30 spread daemons in my segment how much additional latency is 
there going to be?

I believe this is why the spmonitor shows the "last" which was the server 
having a high number of retransmits.  

Is this a known issue?

How would I best design my system around this problem?

Thanks,
Mike




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