After reading through the ESX 4.0 and vCenter 4.0 Server Installation Guide I noticed the following requirement for adding vCenter to a Linked Mode group;

“All vCenter Server instances must have network time synchronization. The vCenter Server installer
validates that the machine clocks are not more than 5 minutes apart.”

Now this got me thinking…..

If a company had two Data Centers, lets say one in London and one in Amsterdam, They’ve decided they wanted to use vCenter Linked Mode to help them manage both Data Centers from a central location. According to VMware’s documentation this wouldn’t be possible due to the time difference between the two cities, London GMT and Amsterdam GMT+1 would mean that the vCenter Server clocks would be 1 hour apart.

Could this problem be fixed just by changing the vCenter Server’s clock in one of the Data Centers? Or would that then cause issues with other services running on that server?

I’m sure many people reading this, especially in the US, are thinking that this could become an issue as many US companies have offices spread across the country, which spans many time zones.

Below is a map of the worlds time zones, have a look at it and see if any of the companies you work for, or have worked for would have problems if they decided to use vCenter Linked Mode.

I think vCenter Linked Mode is a great feature, but I think this could be a limiting factor for a lot of larger companies.

I have contacted VMware to find out if they can shed any light on this, I will update this post as soon as I hear anything. If you know of a way around this problem please post a Comment or drop me an Email.