Judging by the comments on my last blog entry (on CIO.com and other sites owned by parent company International Data Group in various countries and languages) people are very attached to their own way of approaching virtualization, and the vendors and technology they use to help them out.

(I have to say the comments on CIO.com were a lot more balanced and trenchant than a lot of the other sites, at least as far as Babelfish and I can tell through the language barriers.)

IT pros don't like it when someone else (even someone with a good track record in VM implementation and management) says some treasured feature is either irrelevant or, more accurately in this case, not as big a deal as they like to think it is.

In this case, the VM manager was Chris Steffen, principal technical architect at Kroll Factual Data, a credit-reporting and financial-information services agency in Loveland, Colo. The commenters' consensus was that his assertion that dynamic migration is a nice feature to have but far from critical was, at best misguided and, at worst, partisan propaganda or criminal ignorance.

Steffen's point was that it's not a good idea to take a VM running a mission-critical application and shift it from one physical server to another in order to keep workloads balanced. That's not enough benefit to justify the risk of moving a key application while it's being used.

Stupid, shortsighted, head-in-the-sand denial, according to the commenters (VMware users to a one, as far as I can tell).

The ability to move a VM is not only a critical capability, it's perhaps the key measure between grade-school-quality, wannabe-virtualization vendors that can't build live-migration into their Tonka-toy software and real VM(ware) companies who can not only build it, but charge through the nose for it as well.

To be fair, no one denies VMware's VMotion is a lot more sophisticated at VM provisioning, migration and management than Microsoft's stuff. Virtual Migration Manager 2008, which is due to ship commercially in September, is perfectly adequate as a migration and provisioning manager, according to Steffen, who's been testing it forever.

His point had nothing to do with the quality of the migration tools (or their existence, which seems to be a point of debate among VMware partisans). It had to do with the advisability of moving hot servers in the first place.

Which (and this explains why I'm not just complaining about criticism from commenters), is going to be a bigger deal as the VMware-Microsoft competition continues to heat up.