[PAI]

For anyone that is using vmware to run your zimbra box, you may experience some problems with your virtual machines clock gaining time anywhere between 20% to 40% faster than real time, there is a remedy for that through a pretty simple hack.
I don't take any responsibility for potential damage resulting from using this information.
It worked well for me, I hope it works well for you if you have similar problems.

My system is a Athlon 64 3400+ 2gb with a 64bit CentOS 4.2 host and zimbra is on a 32bit CentOS 4.2 guest. It is rock solid after this work around and I have absolutely no problems whatsoever with performance.

1.) setup vmware tools on your guest OS
2.) On the Host OS: go into the .vmx file for your virtual server and insert
tools.syncTime = "TRUE"
This does not help with the speed up, but it will keep the clock right if it falls behind.
3.) On the Host: We are now artifically going to slow down the virtual systems clock. The reason I found for the speed up on my system was that vmware thought my processor was slower than it really is due to the CPU 'slowing' itself in power saving mode and misreporting its speed(right now its shows its MHZ at 1004.598 rather than ~2400). So when the CPU exits power saving mode it results in time elapsing MUCH faster (I gained 2 days in 1 night). VMware-tools does NOT correct for this, it only corrects forwards.
So we are going to go into the /etc/vmware directory and edit the file config with your favorite editor, now add a line
host.cpukHz="2401000"
Where the number is just slightly above your CPUs mHz (or rather kHz)
4.) Also in the grub options (/etc/grub/grub.conf) add clock=pit
example: kernel /bzImage-2.6.9 ro root=/dev/VolGroup00/LogVol00 clock=pit
5.) your virtual system clock will now run a couple of seconds slow each day, but VMware-tools will detect this and sync the clock to the real system clock. Problem solved.



I hope you find this helpful, it took me a couple of hours to get all the information together from seperate sources such as news groups and the vmware forum, so I figured I'd summarize this quick and dirty guide for fellow zimbra users.