I've currently got two zimbra servers... one MTA that's mostly idle all the time and one mailbox server with 2x Dual Core Xeons and 8GB of RAM. I've got 7500 users and about 500 each of IMAP and Web sessions at peak times. Everyone I've spoken to at zimbra has said that this setup should be adequate, and that if I do outgrow it, I should pull the LDAP server off to a 3rd box. I received a lot of help in tweaking the system under 4.5 (NE) from a zimbra tech and the load on it was reasonable.
The problem is that ever since upgrading to 5.0 (NE), this box has a load average of around 6 during the day, and at times it jumps up around 22. The Java process is clearly the resource hog, and I've done my best to tune it according to the wiki. The zimbra tech assigned to my case appears to live in India, so he keeps looking at my server at 4am when the machine is idle and declaring that I don't have a problem, so I'm apparently on my own.
So I basically have two questions: Does 5.0 eat so many more resources that it's normal to see an increase in load after the upgrade? And if it is time to scale out, would I really see that big of a gain by splitting LDAP off to another machine, given that it's only using about 1% of the CPU time? Our server has been between sluggish and useless for the 10 days since the upgrade, so I need to do *something*. Any hints would be appreciated.