[CentOS-virt] Fast clock under VMWare

John Thomas gmane-2006-04-16 at jt-socal.com
Fri Feb 22 19:12:22 UTC 2008

Ray Van Dolson wrote:
> I think the typical fix for the clock-too-fast problem is to boot your
> guest OS with the clock=pit option and then use the VMware Tools time
> synchronization option.

FWIW, I do this and the click still runs slightly too fast.  I put this 
script in my cron.hourly folder and run the VMWare Tools Time Sync to 
fix any resulting slowness.

sleep 2
date --set='-1 second' >/dev/null 2>&1

I do no think the VMWare Tools handles "clock to fast" only "clock too 
slow".  There must be a better way, but I do not know it.

> If the clock is running too slow is where you want to look into using
> one of the 100Hz kernels.

I have found that the benefit of the VM kernel (aka 100Hz kernels) is 
that the load on the physical host is substantially reduced.  I did not 
notice any timing issues/changes from this kernel.

John Thomas

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