I want to design email system for my organization to serves about 25,000 users, I using Zimbra Open Source. The idea of design as shown in Fig.
* I use:
- 4 MTA in DMZ 4 MTA had VIP (10.0.0.10) is managed by F5, run loadbancing
- 2 Mailbox server 2 servers Mailstore: Split load and if one server dies, the remaining server is still operating normally.
- 2 LDAP LDAP operation mechanism MMS (Multi Master Server)
- Hard disk of all the server on the SAN
* According to this purpose I have done the following:
- Install 2 LDAP with MMS
- Install 1 Mailbox
- Install 4 separate MTAs
(I use Zimbra Open Source 8.6)
* My questions are:
- Does this design serve 25,000 users with no downtime (or minimal downtime)?
- How to install 2nd Mailbox which operate in parallel with Mailbox1 (All the users are stored on the 2 mailboxes, load sharing, and if one server dies, the remaining server is still running)
- The installation of 4 separate MTAs are working okay with loadbalacing?