An architecture question, regarding the use of load balancers and/or SSL accelerators in conjunction with a multi-box Zimbra install. We are an edu with 30,000 accounts, and would especially appreciate feedback from other edu's.

We are beginning to implement our dev, test and production servers for Zimbra. We are currently planning to have a load balancer in front of three Zimbra MTAs; the MTAs will also have the Zimbra proxy installed, for IMAP, POP and HTTP. We would like to hear about the experiences of other sites that have used load balancers in front of their Zimbra systems. What special considerations may we have to resolve for this architecture?

Our load balancers also have an SSL accelerator module for SSL decryption. In our legacy system, the load balancers front-ended the SSL traffic, performing SSL decryption; communication with the back-end servers was non-SSL. All systems involved were duly protected by a hardware firewall as well as other security mechanisms.

We are looking for other sites with experience in either or both of these options, particularly with wise words about configuration, pitfalls, etc.

Thanks for your comments.