Good evening to all!

I wanted to take a quick moment to discuss how important it is to wind your watch or – at a very minimum – express the importance of ensuring any virtual deployment runs WITH clockwork.  Notice the lack of “like”.  We want precision and here is why…

A practical comparison is that of your personal watch: a phone, an analog wrist watch, or even a HP digital watch!  If it is slow, would that not throw off your day?  If it is fast, would that STILL not throw of your day?  Late for work, early for a meeting, schedule completely offset, and most likely stress, right?

The same proves true for a typical computer to a virtual computer.

Take your system clock and change it back to 3 hours in the past.  Try networking.  Try authentication with a client that randomizes key codes based on time.  Try … ping.  It will fail and such is the same with virtualization!

When installing XenServer, deploying PVS images from XenDesktop, or utilizing any other virtualization tool, well… time is essential.

Ergo… NTP.

Some of you may have NTP servers in Active Directory, some may use another source.  The point I am driving home is that from installation to utilization of virtual desktops: ensure they are connected to reliable, redundant time servers.  If time skews too much… boom.  High Availability solutions can trip up, virtualization can tank, and the underpinning of what keeps a virtual deployment up and running can skew into an unexpected halt.

I take no risks:

Pool, Tick, Tock

As for XenServer – if you need to manage NTP sources – it is simple as using xsconsole:

Never rely on hardware clocks for software!