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Zimbra on ESX: Multi Server OR Single install

Posted: Thu Jan 22, 2009 5:01 am
by teo
hi all, i'm going to install zimbra on a HP DL580G5 2QUADCORE 20GBRAM SCSI/SAN machine on ESX.

The purpose is to have up to 1000 users in a 64bit ubuntu installation.
My question is: does make sense to plan a multiserver installation following the guide (3 servers)?

does this improve performances instead of single installation ?

Is it a good choice instead of dedicated hardware ?
thanks for any help

Zimbra on ESX: Multi Server OR Single install

Posted: Thu Jan 22, 2009 9:08 am
by L. Mark Stone
[quote user="teo"]hi all, i'm going to install zimbra on a HP DL580G5 2QUADCORE 20GBRAM SCSI/SAN machine on ESX.

The purpose is to have up to 1000 users in a 64bit ubuntu installation.
My question is: does make sense to plan a multiserver installation following the guide (3 servers)?

does this improve performances instead of single installation ?

Is it a good choice instead of dedicated hardware ?
thanks for any help[/QUOTE]
User activity is what hammers a mailbox server and mail processing is what hammers an MTA server. In a single-server environment the loads will be quite "peaky".
Separating out the mailbox and MTA functions onto separate servers will help to keep the UI snappy for end users at all times, even when the MTA server is being thoroughly hammered by huge mail flows.
1,000 users IMHO should work fine on two mailbox servers and one MTA server. If you have resource-intensive users or a lot of simultaneous users, you might need a third mailbox server. Consider also putting in a Zimbra proxy server, so users won't have to know on which mailbox server their mailbox lives, and you can move mailboxes between servers as needed transparently to the end-users.
Hope that helps,

Mark

Zimbra on ESX: Multi Server OR Single install

Posted: Thu Jan 22, 2009 11:38 am
by teo
Thanks a lot Mark,

i will plan a multiserver installation on esx.

i'll use ubuntu 64 bit and zimbra 5.11 oos on each server.
do you have any suggestions about raid level for mailbox server in this esx situation ?
thanks again

Zimbra on ESX: Multi Server OR Single install

Posted: Thu Jan 22, 2009 12:26 pm
by L. Mark Stone
[quote user="teo"]Thanks a lot Mark,

i will plan a multiserver installation on esx.

i'll use ubuntu 64 bit and zimbra 5.11 oos on each server.
do you have any suggestions about raid level for mailbox server in this esx situation ?
thanks again[/QUOTE]
Two things, I'd wait for 5.0.12, probably out before the end of this month, and; for RAID levels and SAN partitioning, look for the Performance Guidelines for Large Deployments wiki doc and see the disk-related section. I wouldn't start off making any other changes from a default install as per that document (except to set vm.swappiness = 0). But generally speaking, RAID10 is much preferred over RAID5/6 except for /opt/zimbra/backup.
Not to be pushy, and I'm happy to help here via the forums, but we have done paid consulting engagements to get folks planning a large deployment/migration up and running quickly. Like with any complex software, there are a number of little things with Zimbra that can turn out to be "gotchas" later. With SANs, one common mistake we see is setting one of the mount points to /opt/zimbra. The Zimbra installer, when you are doing a clean upgrade, tries to delete the whole /opt/zimbra tree and will of course fail trying to delete that mount point. For a new install, sometimes you want to do a few test installs first. Having to reconfigure mount points on the SAN to do those test installs is a big waste of time.
Hope that helps,

Mark

Zimbra on ESX: Multi Server OR Single install

Posted: Fri Jan 23, 2009 11:39 am
by jholder
One quick suggestion:
Go with 32-bit if you can. The reasoning is pretty simple:
On 64-bit you need 4gb per server. On 32-bit you only need 2GB.