[raj]

Hi..Zimbra runs just fine on Vmware ESX or ESXi ..not the Vmware Server
number of users is not the measure of the complexity and other hardware specs. what you need to know before hand is at least the following

1) what avrage storage space you giving per user/ or a user will use
2) how heavy is the mail traffic..total number of messages in and out a day
3) are you runnning ay MX gateways/Appliances for AV/AS or you will be using Zimbra edge MTA itself
4) how many concurrent users will use POP/SMTP/WEBMAIL and IMAP

once you post above basic params, many people here on the fourms can chime in and tell you what they running.

for 3 server setup with SAN.. you can do the following multi server install setup..just one eample no VMWARE direct intall on server

Server 1: MX + AV/AS + LDAP (master)
Server 2: MAILBOX1
Server 3: MAILBOX2 + LDAP (slave)
SAN --> /opt/zimbra/storage
SAN --> /opt/zimbra/index
SAN --> /opt/zimbra/db


with VMWare..you can actutally create more nodes for multiserver install.

SERVER 1
VM1 - Zimbra MX 1 + AV/AS
VM2 - Zimbra SMTP 1
VM3 - Zimbra Proxy (optional)
SERVER 2
VM1 - Zimbra MX 2 + AV/AS
VM2 - Zimbra LDAP (master)
VM3 - Zimbra Mailbox 1
VM4 - Zimbra Mailbox 2
VM5 - Zimbra SMTP 2
VM6 - Zimbra Proxy (optional)
SERVER 3
VM1 - Zimbra MX 3 + AV/AS
VM2 - Zimbra LDAP (slave)
VM3 - Zimbra Mailbox 3
VM4 - Zimbra Mailbox 4
VM5 - Zimbra SMTP 3
VM6 - Zimbra Proxy (optional)

SAN to store mails


all the above just my opnion..
raj