Recently I had a VMware ESXi (4.1 and 5.0 are the same) environment and creating three VM server (Windows 2008 R2 Standard). I found a interesting thing is whenever I manually changed the ESXi host time a big value let's say 5mins or 10mins.
And roughly within one hour later, all three VMs have been changed the time, like "The system time has changed to 2011-12-29T07:27:38.500000000Z from 2011-12-29T07:22:41.502723100Z." EventID is 1, and user is "system". Before that, the time configuration on ESXi host is showing red (refer to picture1). And after 10~20 minutes later, the host is not responding. (refer to picture2). After the VM's time been changed, the time configuration on ESXi host is showing normal again.
I checked everything with the w32time service inside the windows registry and disable all NTP, even disable w32time service. This one seems to happen again and again.
Then I enable the logging with w32time service and found the SyncToCmos is yes, I suspect the root cause is VM try to sync with hardware sometimes. Would like try to disable it and see how is going. Any idea with this kind of issue?
I did add the following content into configuration (.vmx) file and reboot the VM as well.
tools.syncTime = "FALSE"
time.synchronize.continue = "FALSE"
time.synchronize.restore = "FALSE"
time.synchronize.resume.disk = "FALSE"
time.synchronize.shrink = "FALSE"
time.synchronize.tools.startup = "FALSE"
The reason why we will pay attention to this issue is because our environment don't have any connection to internet which means we can't use NTP server to sync ESXi host. Then we ran one script to manually sync the ESXi host with one of the VM which is the master clock of our system. But everytime we have a big change such as 3 minutes, sound like ESXi host will correct the VM again and then the master clock is not correct any more and trigger the problem.
Your reply will be greatly appreciated!