slow clock on FreeBSD 7.2 on vmware

[Steve Polyack]

On 12/18/09 12:39, Chuck Swiger wrote:
> Hi--
>
> On Dec 18, 2009, at 9:24 AM, Steve Polyack wrote:
>    
>>> I haven't used Xen, but for ESX: I may be wrong, but I'm pretty sure that the vmtools available for FreeBSD do not support synchronizing the host time to the guest OS.  I know it is supported (and works) for Linux, but by what mechanism I do not know.  On OpenBSD the kernel can be built to present a device which will use the "synchronize time with guest" feature of VMware to provide a clock source which can be specified in ntpd.conf.
>>>
>>> Perhaps you're right and all it takes is the switch in ESX.  I've disabled ntpd on one of my VMs and I'll see if it drifts any by tomorrow.
>>>        
>> FYI the system has started to drift on the order of 100ms every 6 hours.
>>      
> OK.
>
>    
>> This leads me to believe that the "synchronize time with guest" feature of ESXi is not sufficient in FreeBSD with VMware tools.  While using NTP, the system would reliably keep in sync within 30ms of local NTP relays.
>>      
> You supposedly need to re-run it periodically or enable an internal in some .vmx config file; see "Enabling Periodic Synchronization":
>
>    http://www.vmware.com/pdf/vmware_timekeeping.pdf
>    
Even with the following set in the virtual machine's .vmx configuration 
file, the clock still drifts without ntpd:
tools.syncTime = "TRUE"

$ ntpdate -q pool.ntp.org
server 209.114.111.1, stratum 2, offset -2.093494, delay 0.10614
server 66.250.45.2, stratum 2, offset -2.082546, delay 0.04468
server 169.229.70.201, stratum 3, offset -2.092357, delay 0.11055
21 Dec 11:29:06 ntpdate[12781]: step time server 66.250.45.2 offset 
-2.082546 sec

The vmware_timekeeping.pdf document also states that "By default, the 
daemon checks the guest operating system clock only once per minute.", 
meaning that we shouldn't have to adjust any of the other options to 
maintain synchornization.

> If this doesn't work in FreeBSD guest VMs, has anyone filed a bug report with them?
>    
I have not filed a bug report.  I'm using open-vm-tools and have not 
tried the VMware-provided tools yet.  I'll give them a shot if I get a 
chance and I'll see if will actively sync the time by itself.

Can anyone else chime in on whether or not the "tools.syncTime" option 
and setting kern.hz=100 have been sufficient in keeping the time in sync 
with a FreeBSD guest?