Kris Deugau put forth on 11/9/2010 11:07 AM: > That said... Yeah, upgrade the hardware now - I'd even say go for more > than 8G of RAM if you can stuff it in, because if you're running a > memory hog like SpamAssassin on the same machine as your core mail > daemons and webmail, you'll need it sooner or later - and going into > swap when running something like SA is a good way to cause *everything* > to slow to a halt.
He's not running SA on this box so that's not an issue. From what I understand he is planning on supporting multiple hundreds of simultaneous IMAP users, and ton top of that, local webmail users with his httpd/webmail app running on this same system. In that case, he'll need all the CPU he can stuff into the box as well as tons of RAM. CGI based webmail apps are CPU/RAM hogs with many concurrent users. The Proliant Dl180 g6 box he has will scale to 192GB RAM in 12 DIMM slots, but getting it there gets expensive due to the cost/DIMM at 16GB density. Using fairly inexpensive 4GB DIMMS he could occupy 6 of the 12 slots for a 24GB capacity. That should be plenty for the requirements the OP has described so far. If not for the webmail requirement, he could get by with much less CPU and RAM, and only have to worry about disk array performance, which is the main bottleneck for IMAP. For the number and type of users he's talking about, as I mentioned before, he should have at least 8 spindles of hardware RAID5/6 to carry the load without bogging down. However, the OP has made it clear that this is an expansion system for new customers, and the load will start at zero and build as clients are added. It will not apparently have high user load until some point in the future. If indeed at some point it will be handling a mix of 1000 or more concurrent IMAP and webmail users, it would be beneficial to load the box up with performance now, rather than downing the system for upgrades later, IMO. -- Stan
