[imp] Server setup for customer base of over 10,000

[Robert Sand]

Hello,

We are running into a problem with our Horde/Imp server at our 
university.  When we converted to the CVS/head version of horde and imp 
last year we found that we could no longer use multiple servers for 
web/imap due to session information.  We would like to know what others 
are doing for a user base of over 10,000.  This would include dns, 
servers, etc.

We are currently running the web server on a 4 processor Dell box with 
redhat 8,  and the sql server on a seperate box.  We have tried to use 
multiple imap boxes at first not running imapproxy and then running 
imapproxy.  We have run into the same problem each time that problem is 
that when there are a certain number of connections on the web box the 
imap boxes degrade to the point of not being usable which then degrades 
all other means of reading mail on campus.  All imap boxes are attached 
to a 4 processor Sun box that has a fibre connection to a SAN for the 
Inboxes.  The Sun has been optimized for the SAN connection.

We have found that once the apache web server on the web box gets to a 
certain number of connections it spirals out of control spawning many 
threads.

We would like to have a number of web boxes in a round-robin dns pool so 
that if a user goes to one url they will be evenly distributed to the 
whole.  Like I said this did work for use until the upgrade to the 
CVS/Head version of Horde/Imp. 

-- 
Robert Sand.
mailto:rsand at d.umn.edu
University of Minnesota, Duluth
Information Technology Systems and Services
144 MWAH
218-726-6122        fax 218-726-7674

"Walk behind me I may not lead, Walk in front of me I may not follow,
 Walk beside me and we walk together"  UTE Tribal proverb.