How to design Zimbra mail for large environment?

[tuandungtb89]

Hi all,
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?

Many thanks!

[cayaraa]

- 2 Mailbox server 2 servers Mailstore: Split load and if one server dies, the remaining server is still operating normally.

mailboxbox servers as the exist now they don't replicate each other or do automatic fail-over/load balancing. If you have two mailbox servers then one user's account will only be on one mailbox server. If that server goes down their account because unavailable until the server comes back up. The "load balancing" is more of a static thing. In stead of having one huge mailbox server you can create several smaller ones and have all of your accounts spread out over them.

-Aaron