32 or 64 bit on esx ?

[teo]

hi all,
we are working for make a multiserver installation of zimbra 6.05 on 3 separete esx 3.5 sun bachines based on hp dl380. this solution must server up to 1000 users (90% pop users) connected via outlook/express clients.

I will plan to have 3 zimbra server in multiserver installation mode:
1) ldap 2gb ram
2) mailstore 4gb ram
3) mta 2 gb ram

all machines will run ubuntu 8.04.4 server

my BIG question is:
does is better 32 or 64 bit ?
(for my experience 32bit is better)
please help me
thanks

[Matuscak]

I don't know about Ubuntu, but in general I think you're better off building Zimbra on a 64 bit platform. Particularly for large environments you're going to want lots of ram. We're using Zimbra NE on 64 bit CentOS and it works fine.

[teo]

thanks for your answer,

is this true for vmware esx installation also ?

[Matuscak]

Originally Posted by teo

is this true for vmware esx installation also ?

Assuming the ESX hardware has VT support and can run 64 bit OSes, sure. That's how ours is set up.

[PRL]

Thought I would give my two cents on this. We use the following specifications for 175 Zimbra users...

VMware ESX 4.0 Update 1
CentOS 5.4 64-bit
8 gigabytes of memory
2 vCPUs

We have about 75 users using the AJAX interface and the rest are POP. We have been using Zimbra for over a year, and so far no problems related to ESX, virtual hardware, or 64-bit operating systems. In general, I feel its best to use 64-bit operating systems and applications whenever possible, especially in the server environment. The desktop environment is a completely different ball game.

[teo]

do you have a multiserver installation ? (ldap +mailstore+mta)
what do you think about multiserver installation in 32bit instead of a single intallation 64 bit for 1000 user ?

thanks

[Matuscak]

Originally Posted by teo

do you have a multiserver installation ? (ldap +mailstore+mta)
what do you think about multiserver installation in 32bit instead of a single intallation 64 bit for 1000 user ?
thanks

We're running on a single server. I think you probably do want multiple servers at the 1000 user level.

My recollection from the Zimbra training class is that the recommendations were to always use 64bit OSes if you can.

One of the nice things about Linux is that pretty much everything has 64 bit versions, so its really quite transparent to make the move. As we replace older systems we've moved all of them to 64 bit and I can't think of a reason why I would want to build a 32 bit system if the hardware supports 64.