[imp] DB Error :: connect failed - sql shared session management

[Michael Yingbull]

We've encountered the above error when using jMeter to do some 
performance tests against a new webserver running IMP. 

At a fair low load, we hit a point where there are a number of failures 
that come up when the test application tries to do a function inside IMP 
-- and it fails out with the dreaded "Purple Screen of Death" :-) 
showing the above error.   For some reason the server settings aren't 
allowing it to keep up with requests.    It is failing contacting the 
mysql server for session info (we're using mysql to store the session 
info amongst a cluster - this just happens to be the first machine in 
the cluster).

I configured horde to use the sql pear driver.

Are there any tuning changes that should be done to the mysql server 
(mysql 4), php (4.3.7), or the linux server that it runs on?

Currently mysql runs on the same machine as the webserver.    Other than 
our testing, it isn't being used currently.

Thanks for any advice you may have.