Lotus Domino-like mailstore replication?

[mbrijun]

Hi,

we are looking into several options for our mail system. Domino vs Zimbra NE. Zimbra NE lists high availability as one of its features. I would like to know if setting up a Red Hat cluster is the only way to get several Zimbra mailstore servers to be the replicas of each other? Or would it be enough just to go with the multi server installation?

Domino is very good in maintaining replicas of the mailboxes on various servers with minimal config. At a price though. Can it be achieved with Zimbra relatively easily, because judging by the RH cluster installation document, expensive hardware like SAN is required for a successfull deployment.

Thank you.

[mmorse]

Obviously the best & supported method is RHEL + RHCS + SAN

However...another way to accomplish failover would be to use DRBD and Heartbeat.
DRBD is basically a form of 'network RAID', while heartbeat monitors a server and can make a backup come online in case of a problem.

One setup is described in this thread:http://www.zimbra.com/forums/adminis...mbra-drbd.html

Other relevant/some notes:
Zimbra, DRBD and Hearbeat, with 2 servers not in the same LAN
http://www.zimbra.com/forums/adminis...by-server.html
HA Open Zimbra Idea - MailStore via http rather than file system.

Again, it's certainly most suggested (and supported) to use the NE version RHEL & RHCS. And if your going NE anyway (Backups, Attachment Indexing & view as HTML, HSM, ZAD, MobileSync, iSync, Outlook connector, delegated admin privileges, etc, etc) you might as well spring for the supported clustering method (using a SAN). But there's technically nothing stopping you from using NE & another clustering solution-you'll just be asked to disable it when support does any troubleshooting.

[mbrijun]

Hi mmorse,

thank you very much for the links, I am studying them now. Just a quick question - everything that I have read so far describes an active-passive configuration. Is it possible at all to have an active-active one?

Thank you.

[mmorse]

DRBD synchronously replicates data to another node in an Primary/Active to Secondary/Passive configuration. In the event of a failure, Linux Heartbeat will promote the Secondary/Passive node to an Primary/Active state.

Correct me if I'm wrong-when you mention active/active, but it kinda sounds like you want some form of local load balancing so users could interact with either system?
With Zimbra, each mailbox account is assigned/configured to one particular mailstore server. If you need to move user's to a different box, say they are now working in your Chicago office and need to be on a server that's closer to Chicago -or just to balance your server usage- you can move them between servers with zmmailboxmove or the nice admin console GUI. -They can still always auth/signin via either system, then their redirected to the appropriate mailstore.

What are your expansion plans? (as actually I don't know how big of an organization/# of users we're talking).
Are your company/organizations requirements as such that you'd be ok with relying on the backups? (You can also then cue up incomming mail on a standby box that has the necessary mx records-actually this is a good idea for any type of setup, zimbra or not.)
You could build up a multi-server install, then if you ever can afford/require it move to a SAN & add mailstore standby boxes as needed.

Some examples:
6_Box_Multi-Server_Example
Sample Multi-Server Deployment w/ RHCS

[mbrijun]

Hi mmorse,

I am beginning to understand how it works in Zimbra and how it is different from Domino. In Domino each mailbox can be on multiple active servers at the same time, and it will be replicated in real time between them by Domino itself, without relying on the OS, whereas in Zimbra each mailbox store will only have its own subset of mailboxes.

I will dig into the links that you have sent me - much appreciated.

Have a good weekend.

[mmorse]

lol-it was just 2 pics
The marketing/sales guys can give you a far better customized walkthrough; throw an email to sales@zimbra.com

Don't forget about the advantages to zimbra's method, such as single-instance storage; you send an email to 50 employees & only one copy of a message is stored per mailstore. Dramatically cutting the amount of storage needed.

§Decoupling of meta- & message-data

•Fast store for meta-data

•Multi-volume message store & HSM (automatically move data to SATA, your older SAN, etc.)

§Co-location of user data: Mailbox, Index, Messages

•For longer-lived server data

•Performance (reduced disk I/O)

•Caching (reduced disk I/O)

•Easier restore

§Consolidated stateful mailbox tier

•No edge caching otherwise!

•Latency of multi-process chaining

•And reduced CPU overhead of multi-process chaining