I have been testing ZCS OS and we are looking at rolling this out as a solution in the future.
I am running ZCS OS 5.0.18 on Ubuntu Server 8.04, running as a vm on ESX 3.5 (soon esx4).
I have been looking at ways to host the mail stores that will provide a flexibility for growth, backup and administration.
The 1st option I have looked at is hosting this on our NetApp San via CIFS. I have mounted a share and was testing. I found this performed fine while using the zimbra web interface, but as soon as I moved to external IMAP clients (outlook 2003, Thunderbird etc), I started to get issues.
When moving messages into other folders I'd get;
the mail server responded: UID COPY Failed - in the client.
imap - UID COPY failed
com.zimbra.common.service.ServiceException: system failure: Caught IOException executing com.zimbra.cs.imap.TcpImapHandler@1522e40
in the zimbra mailbox.log.
As soon as I moved the Zimbra mail stores back to the local disk (/opt/zimbra/stores) all imap clients behaved normally.
Doing some digging this looks like it's related to zimbra's use of hardlinks and the fact that cifs (and nfs?) don't support them. Can someone confirm this and offer any advice on using CIFS or NFS to host the zimbra mail stores?