Virtualization free-for-all

Barely 10 years ago, I ventured that all systems would be virtualized, and that IT law would dictate that no OS may have unregulated direct contact with system or storage hardware.

That position drew a lot of scorn from knowledgeable people. My stance on virtualization was old school, ’twas said, a throwback to timesharing and mainframes, and antithetical to personal computer philosophy. PCs are small and cheap, so if you need another instance of an OS, you buy another PC. That’s where we stand now. We’re diving down, down toward the disposable server, the machine that’s cheaper to rip and replace than it is to diagnose and fix.

Don’t place your faith in trends, friends. The next cut of x86 virtualization is here. It calls for bigger servers, which I predict you will purchase willingly. As of this week, the two biggest names in microcomputer virtualization -- Microsoft and VMware -- are giving away their banner server virtualization products. Neither vendor can claim that its work is anywhere near finished, which means that spending will continue on the development of products that, like Web browsers, will either be free or dirt cheap from now on. But that’s how it should be.

The prophesied ubiquitous virtualization is being hastened by two fairly large steps of late. In addition to becoming free software, VMware and Microsoft host/guest virtualization solutions now support running 64-bit guest OSes on 64-bit hosts. This takes the hypervisor out of the critical path for those IT operations looking to take early advantage of next-generation x86 virtualization.

The hypervisor, a thin layer of privileged software dedicated to managing virtual OS instances, the layer that obviates the need for a full-blown host operating system, is not with us yet. The hardware-accelerated virtualization technology that Intel and AMD are shipping now, but which most vendors are taking up slowly, will kick hypervisor development into gear.

A hypervisor will be nice, but 64-bit host/64-bit guest support is more than a baby step. This, coupled with fast CPUs and memory, and soon to be boosted by hardware acceleration, means that it’s no longer necessary to make the host OS functional for use by applications. In other words, if you plan to host more than one guest OS, it makes sense now, and it will make even more sense after hardware acceleration, to strip the host OS down to its skivvies. Linux strips beautifully if you’ve got just a little bit of developer in you. A one-calorie Linux, plus VMware Server, make a cheap host for whatever 32- or 64-bit guest OSes you choose. Microsoft Virtual Server requires Windows, so stripping the host takes more time, but after you whittle it down, you can burn it to a DVD image and tote it around as your home-brew hypervisor. It’ll tide you over.

The very next ship to come sailing in will be hardware-accelerated virtualization. AMD’s Revision F Opteron is overdue, but AMD’s FX-62 power-user platform and Intel’s Core Microarchitecture have 64-bit accelerated virtualization baked in. VMware and Microsoft have “experimental” support for Intel’s variety of acceleration implemented in their downloadable code. It won’t be experimental for long. Make sure the servers you purchase from here on have either AMD Opteron Revision F or Intel Core Microarchitecture CPUs. The Intel gear will be easy to spot, but for Opteron, the easiest tip-off for Revision F is support of DDR2 RAM.