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 From:     Daniel Wyss
 To:       imp@lists.horde.org
 Subject:  RE: [imp] Help Req. : Sizing a Horde\IMP system for 12,000 users
 
 Speaking from experience combining Sun hardware/Cluster/and Imp/Horde:
 I would first separate out your web server(s) from your mail and DB
 server(s) especially if you plan on using a secure web server and/or
 IMAPS. For this web server, use your best hardware, you may experience
 high loads like we did using SSL, so you may also consider purchasing
 crypto-cards if you run into this problem. The next (big) step would be
 to run a scalable apache server (via Sun Cluster 3.0). This starts
 getting pretty expensive, cost of licensing Sun Cluster 3.0 software,
 the cost of agents, the cost of the approved architecture, and the cost
 of support. Plus you definitely want to get some training if you're
 going to run a Sun Cluster. (personally I wouldn't recommend this route
 unless you really need HA and/or scalability.) I think option 2 from
 Eric's message down below might be the sensible route in your situation.
 
 Background:
 We have been running Imp/Horde here at the University of Colorado since
 the Summer of 2000 exclusively on Sun hardware. We initially opened it
 up to existing students as an alternative option to pine/elm or
 imaping/popping. The existing students had the choice to migrate over
 from an older mail server to this WebMail system, and all new incoming
 students were giving an account to this newer system. That first Fall
 semester we started with 5000 user accounts, and today there are 40k. We
 started off with (1)E3500 with 6 336MHz processors 2Gb of memory which
 served as the mail (IMAP only) and mysql backend. The Front-end web
 server was also a E3500 with 6 400MHz processors and 3 Gb of memory.
 When we hit about 30k user accounts we started experiencing high load on
 both servers. Granted, we do add some load with some in-house tweeks to
 the IMP/Horde software for quota and affiliation check, as well as doing
 secure IMAPS and SSL. We ended up with a soon to be 6 node V480 Sun
 Cluster 3.0 system that is running scalable apache serving the front-end
 (running IMP/Horde). For the backend, I ended up writing an agent for
 both mysql and uw-imap and this is in a 2 node cluster running (2) V880
 (one with 6 ultra-sparc-III 750MHz chips and the other with 8, one has
 12 GB and the other has 16GB of memory). It's a screaming system now. I
 have had my hands in this since the beginning, so if you want some more
 info about what we are doing here and what we have learned, feel free to
 contact me.
 
 ******************************************
 Daniel Wyss
 IT PRO, Central and Unix Services
 Information Technology Services
 University of Colorado, Boulder             
 3645 Marine St, CB 455
 Boulder, CO 80309-0455