I can sync time of win7 from a ntp linux server manually.
I have noticed that our VMWare VMs often have the incorrect time on them.
Once this (/usepmtimer switch) was done the clock was dead on time. I originally noticed this because VMware gave me a helpful tip on my laptop, but this page mentions the same thing: Quote from : VMWare tips and tricks Power saving (Speed Step, C-states, P-States,...) Your power saving settings may interfere significantly with vmware's performance. CPU frequency This should not lead to performance degradation, outside of having the obvious lower performance when running the CPU at a lower frequency (either manually of via governors like "ondemand" or "conservative").
Ntp not updating time
No matter how many times I reset the time they keep on desyncing. What do other people do to keep their VM time in sync? according to VMware's knowledge base, the actual solution depends on the Linux distro and release, in RHEL 5.3 I usually edit /etc/and append this parameters to the kernel entry: divider=10 clocksource=acpi_pm Then enable NTP, disable VMware time synchronization from vmware-toolbox and finally reboot the VM A complete table with guidelines for each Linux distro can be found here: TIMEKEEPING BEST PRACTICES FOR LINUX GUESTS
language=en_US&cmd=display KC&external Id=1006427 I'll answer for Windows guests.
Resolution: To resolve this problem check with the hardware vendor to see if a new driver/firmware update is available to fix the issue.
Note The driver installation may add the /usepmtimer switch in the file.
(I assumed it would be posible to set this as a parameter / config option during tools install) After a bit of searching I found a way to do this in a VMware article called “Using the VMware Tools Command-Line Interface“.
So, if time sync is disabled, you can enable it by running the following command line in the guest: Additional Notes For some (IMHO stupid) reason, this utility requires you to specify the current as well as the new value 0 = disabled 1 = enabled So – if you run this command on a machine which has this already set, you will get an error saying – “Invalid old value“.
There are other good ones that you can find using a web search. With NTP switched on ( I am using the default which is - ) I find that when I go to dashboard/settings it is all greyed out and the time displayed is always slow - a lot slow like over 24 hrs sometimes.
Obviously, the closer the time source is to you, the better the accuracy. But if I hover over NTP the grey disappears and it picks up correct date and time.
The ESXi host was configured to get time updates from an internal time server.