multi-tenant & multi-server install - appliance vs standard method
We are in the process of planning a Zimbra 8 multi-tenant deployment. I've been reading the admin guide and it seems pretty straight forward, we will most likely separate the mailbox role from the mta and ldap, however I have a few questions and was wondering if anyone here had any recommendations based on best practices or experience.
This is a new install, so there's nothing we are upgrading from, so I have no limitations as far as the config goes.
I guess the first question is appliance vs standard install on Ubuntu, etc - we've been using the appliance for standalone servers with a lot of success, but I was wondering if there are any advantages or disadvantages with a multi-tenant install that will need to scale over time?
Second question is role separation - I'd like mailboxes on their own server, but as far as ldap and mta, any real reason to isolate those? In the appliance it seems to force you to use a separate appliance for each role, but in the standard install I believe I can have more granular option and merge a couple (correct me if I'm wrong on this).
Initially we'll have a single mailbox server but I can imagine this scaling out quickly and having multiple within the next 12 months if that has any bearing on your recommendations on role separation for ldap and mta.
We haven't deployed anything yet, still in the design phases so I'm really open to anything on this.