Page 1 of 2

Question about HA setup

Posted: Fri May 18, 2007 9:29 am
by sgtstadanko
Hi All,
I am looking for advice in setting up Zimbra in HA mode. I want to run 2 servers so that if one dies, fails or runs out of disk the other server will pick it up. Whats the best way to go about doing this. I already have ZCS 4.0.2 running under FC4 and need to choose the correct OS on my new server to make this work properly and was not sure whether Ubuntu or RHEL4 was the way to go.


Thanks,

Bill

Question about HA setup

Posted: Fri May 18, 2007 9:49 am
by Klug
The best (and only supported) way is to use Zimbra NE with RHEL4 and RHCS (Red Hat Cluster Suite).

Question about HA setup

Posted: Fri May 18, 2007 9:52 am
by sgtstadanko
Is RHCS part of RHEL4 or do you have to purchase that.

Question about HA setup

Posted: Fri May 18, 2007 10:26 am
by Klug
It seems (from RH website) to be an additional layer (ie price) to a RHEL subscription : http://www.redhat.com/software/rha/cluster/

Question about HA setup

Posted: Fri May 18, 2007 12:37 pm
by andreychek
[quote user="sgtstadanko"]I am looking for advice in setting up Zimbra in HA mode. I want to run 2 servers so that if one dies, fails or runs out of disk the other server will pick it up. Whats the best way to go about doing this. I already have ZCS 4.0.2 running under FC4 and need to choose the correct OS on my new server to make this work properly and was not sure whether Ubuntu or RHEL4 was the way to go.[/QUOTE]

Hey Bill,
Though not supported by RedHat, Ubuntu or Zimbra, another way to accomplish failover would be to use DRBD and Heartbeat.
DRBD is basically a form of "network RAID", and heartbeat monitors a server and can make a backup come online in case of a problem.
The setup is described in this thread:

Good">http://www.zimbra.com/forums/showthread.php?t=2845&highlight=drbd
Good
luck!

-Eric

Question about HA setup

Posted: Fri May 18, 2007 2:01 pm
by Klug
CentOS obviously proposes an equivalent to RHCS.

But not supported either.

Question about HA setup

Posted: Wed May 23, 2007 6:07 am
by russgalleywood
Hi Guys,
I too am interested in this also for failover purposes.
I am new to the Cluster idea so have some simple, perhaps even idiotic questions!

Here goes...
If you have NE version of Zimbra then it can be configured to use the Redhat/CentOS Cluster Suite with no additional configuration other than that required in the Suite setup instructions? (Obviously, doing this with CentOS is not supported)
No additional Zimbra license is required for the additional Server in the Cluster?
Is it really worth doing it anyway?
I am most concerned that I could be doing more harm than good this way as it is something else to go wrong! Is it in fact better to just create replica LDAP and MySQL servers and just keep good backups?
Thanks
Russ

Question about HA setup

Posted: Wed May 23, 2007 6:50 am
by mmorse
A little more involved than that-most make use of a SAN

RHCS methods:

Clustering on single-node config

Clustering on multi-node configs

-and people often fail to follow the multi-node cluster upgrading procedures for that
Your not changing the amount of users-no license change to Zimbra. RHCS pricing though.
For large companies or those who want serious reliability for the mailboxes-it's worth doing. -everyone's needs are different, and there are many ways to do clustering as well, but zimbra (the company) can't be expected to cover them all with support :)
WIKI multi-server stuff

OS multi-server install guide

NE multi-server install guide

Question about HA setup

Posted: Wed May 23, 2007 6:55 am
by gmsmith
Russ,
There are no additional software licenses required from Zimbra to introduce a cluster, however introducing a cluster requires some common storage between the two servers (shared disc, san, something..), fencing, and some other things. You may want to look at:
Clusters">http://www.centos.org/docs/5/html/Cluster_Suite_Overview/s1-hasci-overview-CSO.html
Clusters
are very worth doing if you need them :)
You may want to just maintain your backups, copy off machine and then do test restores every once and a bit.
As a side note, the information you got regarding LDAP and MySQL while you were traveling was crap. :)

Question about HA setup

Posted: Wed May 23, 2007 6:57 am
by mmorse
[quote user="gmsmith"]As a side note, the information you got regarding LDAP and MySQL while you were traveling was crap. :)[/quote]

Might want to explain what you meant...that could spin multiple ways...