SOLVED: Time Clock Stops in FreeBSD 9.0 guest running under ESXi 5.0

Adam Strohl adams-freebsd at
Fri Aug 3 07:59:14 UTC 2012

Doh, correct URL for the forum post is:

On 8/3/2012 14:38, Adam Strohl wrote:
> Just a heads up on the original issue, which is FreeBSD's timer/clock
> stopping under ESXi 5.0 and some later versions of VMware Workstation.
> I've gotten a few direct messages that this thread ranks high on Google
> but people are missing the solution.  A few months ago I found this
> forum posting (I believe this was linked in this thread already)
> The long and short of it is that changing the kern.timecounter sysctl
> value to ACPI-fast or (ACPI-safe if you're not running 9.x yet) fixes
> the hanging issue so far for us.
> To temporarily enable it under 9.x:
> sysctl kern.timecounter.hardware=ACPI-fast
> Pre 9.x (which doesn't have the ACPI-fast mode):
> sysctl kern.timecounter.hardware=ACPI-safe
> To make this persist across reboots and be enabled by default add this
> line to your /etc/sysctl.conf
> Under 9.x:
> kern.timecounter.hardware=ACPI-fast
> Pre 9.x:
> kern.timecounter.hardware=ACPI-safe
> Hope this helps anyone running across this issue.

Adam Strohl

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