[SOLVED] zimbra muiltiserver installation

[washo]

We are wondering about the requirements for a possible Zimbra installation of about 300,000 users, and were going for the Open Source version. We have been reading the recommended settings and have a few doubts about it.

First, it's not really clear how the multiserver installation works. In our imaginary setup, we would have 1 LDAP "master" server, 2 LDAP replicas and 2 mailbox/store servers per replica. 2 MTA servers would be balanced from the outside using LVS or some other technique pending of decision.

Our question is: from what we've read, it seems that each mailbox server is a full copy of the other. This would mean that we had to multiply by four the disk space alloted for the email accounts. So, if we allocate 100MB for each account, we would have 300,000 x 100 x 4 = 114TB (approx.).

Are we misunderstood? What should be the proper setup for "splitting" the 300,000 accounts among four or more mailbox servers?

Thanks in advance.

[Klug]

Each mailbox server is autonomous, there's no replication _at_all_ between them.

The number of users per mailbox server depends on :
. quota
. CPU/RAM on the mailbox server
. SAN used (or local drives or whatever)
. number of incoming mails
. number of active users
. number of current users (logged in at the same time)
. protocol used by users (https, pop3, imap4)

You're missing some zimbra-proxy in your infrastructure too (with LVS or any other technique), in order to show a single URL to all users, whatever mailbox servers they're on.

[raj]

Originally Posted by washo

Our question is: from what we've read, it seems that each mailbox server is a full copy of the other.

if i understand correctly you are assuming that when you put 4 mailbox server and you create 1 account it kind of automatically replicate/copy that account on 4 server..that is incorrect
Each mailbox server in OSS multiserver install is a separate mailbox server so that you could horizontally expand your user base.
i.e: 100,000 users on each mailbox server and you can host 400,000 on 4 mailbox servers and you can keep adding more mailbox server for more users and can split the load by putting less or more users per mailbox same goes for edge MTA servers

backup/copy/replication of mailbox server is not automatic and easy in OSS version. wiki has lots of help in doing OSS backups ..sync and replication of mailbox is complex and not easy to achieve in OSS version tough there are ways to do this with small downtime of services.

hope this helped..

Raj

[washo]

Originally Posted by raj

Each mailbox server in OSS multiserver install is a separate mailbox server so that you could horizontally expand your user base.
i.e: 100,000 users on each mailbox server and you can host 400,000 on 4 mailbox servers and you can keep adding more mailbox server for more users and can split the load by putting less or more users per mailbox same goes for edge MTA servers

Thanks, that was exactly our question.

Another question: what if one of the mailbox servers goes down? Would the affected email accounts fail silently? Would the rest of users (the ones with accounts in the rest of mailbox servers) still work? Would Zimbra notice of the failure and warn?

And still another question: what is the algorithm to decide the mailbox server where a new account is created? Are they split on a round-robin basis, or is there some complex algorithm that allocates "intelligently" the space in the mailbox servers?

Thanks in advance.

[Klug]

Originally Posted by washo

Another question: what if one of the mailbox servers goes down? Would the affected email accounts fail silently?

Yes, unless you've setup "something" to failover (SAN+VM+software is an example).

Originally Posted by washo

Would the rest of users (the ones with accounts in the rest of mailbox servers) still work?

Yes.

Originally Posted by washo

Would Zimbra notice of the failure and warn?

If you're looking at the admin console yes.
You'd rather want to have your own monitoring tools.

Originally Posted by washo

And still another question: what is the algorithm to decide the mailbox server where a new account is created? Are they split on a round-robin basis, or is there some complex algorithm that allocates "intelligently" the space in the mailbox servers?

AFAIK it's round-robin.
But you can force it when creating the account (though the CoS or by simply choosing it).

[washo]

Thanks for solve all our doubts.