VI 3.5 Update 2 brought a new feature to the table — Enhanced VMotion. I’m still trying to track down some video of the demo we were doing at last week’s IDF, but James Montgomery at Novosco gives a good explanation and some context for why you want to pay attention to this. [via]

Link: VMware ESX and Enhanced VMotion Compatibility | Novosco – Ireland’s virtualisation expert.

The classic VMotion problem of recent times is the customer who buys
tin from a vendor, only to find out that the processor number e.g. 53xx
and 54xx, is actually quite significant. The principle difference which
will prevent VMotion is the addition of SSE4.1 to the 54xx range of
Intel processors (if you previously only had 53xx Intel processors). …

New CPUs are coming out with a facility to ‘turn off’ (mask)
features that would make them VMotion incompatible with other hosts
running older (compatible) CPUs.

For Intel this is called Flex Migration. It is clear that for
processors that are in different families but support Flex Migration
will negotiate the common feature set amongst the CPUs.