VMware’s Mike D is back. He talks about how you can easily VMotion from Intel to AMD, but you should understand the risks involved before doing it on production virtual machines.
Link: A Little Truth: Mike D’s Virtualization Blog: Migrating from Intel to AMD.
I was at a
customer this week that told me Microsoft could migrate live between
AMD and Intel processors and asked why we (VMware) couldn’t. I actually
get this question a lot and so I’m providing some context to the answer
here. …Actually, in
the VC config file you can put in a parameter to prevent VC from doing
any checks. With that parameter you can do migrations between anything
you want. Just be aware that you may shoot yourself in the foot and
it’s not supported as such. … With the Xen based live
migration and Microsoft Quick Migration they do not perform the check
and so you can actually do the migration but your app and your OS may
die as a result.
But what I thought was most interesting was this little vignette as I imagine both chip makers reluctantly putting in this masking switch — although as Mike says later in the post, it usually won’t matter on the kinds of server workloads you want to be VMotioning around anyway.
With all of that
said, VMware went to the chip manufacturers a while ago to see if we
could get a switch where we can turn their advanced features off. They
laughed at us originally. Who can blame them. They put the advanced
features in there to differentiate themselves and sell processor
upgrades. We’re basically telling them not to be competitive. Well,
with virtualization showing up everywhere the chip manufacturers have
decided to put advanced virtualization capabilities into the chips. It
all started with Intel VT-x and AMD SVM. Now both manufacturers are
including a switch that will allow us to turn off certain features and
make the processors look like they have the same features. Intel and
AMD have both added this feature to their recent processor launches.
This is really great since now you can buy a new box with a new feature
set, add the box to the virtualization cluster, and we’ll go ahead and
turn off the advanced features that would normally prevent migration.
