Thursday
27Sep2007
Can new server hardware make virtualization software obsolete?
September 27, 2007 
There was some excitement earlier this month at the Intel Developers Forum in San Francisco over server vendor Hitachi's claim to have made third party virtualization software unnecessary. That would be virtualization as in VMware ESX or open source Xen.
Exciting claims like this are of course what makes the IT world such an interesting place. Think of it: a piece of server hardware that carries its own hypervisor embedded directly in the machine's firmware, obviating the need to buy costly ESX or fool around with not-quite-fully-mature Xen: Virtage, as Hitachi's product is called, is said to be:
...a breakthrough embedded virtualization feature which builds virtualization right into a blade server’s hardware for the first time. It provides customers an alternative to third-party software solutions and thus enables them to decrease overhead costs while increasing manageability and performance..Where did this technology come from? Well, Hitachi is famous for having spent decades and billions of dollars trying to compete with IBM in the mainframe market (mostly unsuccessfully, except in its home market of Japan). And we know that virtualization first arose in the mainframe world, where its development was spurred early on by the need to squeeze every last drop of efficiency out of million dollar room-sized behemoths. In rather obscure fashion, Hitachi claims to have "evolved" its mainframe solution into what it calls "hypervisor-type virtualization" for 64 bit and 32 bit Intel server chips (Itanium and Xeon, dual core and quad core).
If Hitachi's claims are taken at face value, then the Wall Street investors who have bid up EMC's VMware subsidiary to a $30 billion market cap are seriously deluded. However, as the Genie in Disney's Aladdin says, there are a few provisos and quid pro quos.
The first proviso is that Virtage doesn't really seem to be a hypervisor in the sense that VMware and Xen are. Rather, it is more like the Power virtualization feature IBM offers on its pSeries servers. In other words, Virtage is a partitioning utility that installs before the main OS kernel and segments the CPUs on a multiprocessor server into multiple LPARs (logical partitions). The difference is that IBM's firmware hypervisor requires Big Blue's own Power chip and runs AIX (IBM's flavor of Unix), Linux (RHEL or SLES) or the legacy i5/OS (aka OS/400), while the Hitachi product runs on Intel processors with Linux or Windows Server. This is the first time I've seen a server vendor offer hardware partitioning for a Microsoft OS. If Virtage lives up to its promises, that feature alone will make it stand out in the market.
However Virtage seems to offer significantly less functionality than the IBM Power hypervisor. Both products work by creating logical partitions, which are not as flexible as VMware-style virtual machines. A logical partition can be configured to share CPU resources with other partitions, but it generally can't share memory and can only share input/output using complex work-arounds. But while IBM's hypervisor uses micro-partitioning to let you run different OSs simultaneously on the same processor (e.g. AIX and SLES), Hitachi's version seems to require that different OSs (e.g. RHEL and Windows Server) be assigned to different CPUs or groups of CPUs. By contrast, a true hypervisor such as VMware or Xen will let you stack up different OSs on the same CPU. Hitachi's documentation is remarkably vague on this point, and in general exceedingly sparse compared to the hundreds of pages that IBM provides.
The second proviso is that you can only get Virtage if you buy some of Hitachi's brand new and very sophisticated – but far from cheap – blade servers. In other words, because it is built into the firmware of Hitachi's proprietary blade enclosure, you can't use Virtage to consolidate just any old legacy servers you may already own, and you can't even use it with new blades or rack-mounted servers from another vendor. Of course the Power hypervisor likewise only runs on IBM Power gear. But with a third-party software hypervisor like ESX you can run on any compatible Intel- or AMD-based server.
The third proviso is that Virtage isn't available yet. It's scheduled to ship next January. Four months is a pretty long time in the server and hypervisor world these days. By next January IBM, HP and Sun will all certainly have refined their partitioning and virtualization offerings on their house-brand Unix systems, and Microsoft's Windows Server 2008 with its built-in hypervisor will be a lot closer to launch. VMware's stock will probably be even more obscenely expensive than it already is. Given the paucity of information released so far about how Virtage works and how it actually stacks up against VMware or competing server vendor hypervisors, some skepticism is in order at this point about Hitachi's ability to move the needle in this very competitive market.
One thing is clear, though: the relentless train of virtualization marches on.
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