Disable Time Sync and vSphere Upgrade

[VM_Yamato]

Hi Team, 

I have a question about "Disable time sync to Host" situation. Basically, I read following article and I know how to disable the time sync for each vSphere version. (For vSphere 7.0 Update 1 or above and before it)

In short, depends on vSphere version, time sync paramerters are different.

My main question is "when virtual machines has "disable time sync" that run on vSphere 7.0 or before, and when upgrade to vSphere 7.0 U1 or above, should customers change time sync paramerters?"

If customers use legacy vSphere version(before vSphere 7.0) and who plan upgrade to new version(7.0 U1 or above), this point is very important I think.

Reffered Article https://kb.vmware.com/s/article/1189

[jlanders]

vSphere prior to version 7.01 U1 provides a single checkbox in a VM's VMware Tools guest control panel, which enables or disables only periodic time synchronization.  In vSphere version 7.01 U1 and later, this setting should be carried forward and modifying periodic time synchronization should not be necessary.

VMware recommends leaving "Synchronize at startup and resume" enabled, "Synchronize time periodically" disabled and installing a native time synchronization service in the guest (ntpd, chrony, w32time, etc).

[VCPShane]

Hi There. What is the reason for VMware recommending this setting be enabled? Thanks!

[jlanders]

These settings will set the guest VM's system clock to the current time when restarted or power on.