The school where I work is considering going with zimbra for about 15,000 users which would be using the web-based front end only, no imap or pop3 access. I would estimate that each user will recieve about 10-15 email per day. Has anyone used zimbra with this many users and if so what type of hardware would you recommend? Thanks for the help.
We've got installs now with more than that. In general that is very low traffic (message wise) so assuming you'll only have a fraction of the users on at any one time you could probably handle the entire load on a couple servers. Depending on what you plan to use for storage; internal vs external you'll want to decide if you have a frontend (mta, spam, virus, logger, etc) and then store all the mail on a back end. Or build two identical hosts (except for LDAP) and load balance between the two. The 2nd option gives you two MTA's so if one is down you'll always have a backup. Similar for the mail stores where if one is down you can still server the other 50% of your user base.