Wednesday, 26 September 2007

Virtualization – a beginner’s guide to products

Let’s start with a caveat: I’m calling this a beginner’s guide not a complete guide – so, if you know of a product that I haven’t mentioned, sorry, I just ran out of space.

Now the thing is, on a mainframe, we’ve got z/VM, which is really the grandfather of all these fashionable virtualization products. In fact, if I can use a science fiction metaphor, VM is a bit like Dr Who, every few years it regenerates as a re-invigorated up-to-date youthful product, ready to set to with those pesky Daleks and Cybermen, etc.

And, of course, mainframers are all familiar with LPARs (Logical PARtitions), which are ways of dividing up the hardware so it can run multiple operating systems.

The real problem for mainframers is when they are asked to bring their wealth of experience with virtualized hardware and software to the x86 server arena. Where do you start? What products are available? Well, this is what I want to summarize here (for beginners).

I suppose the first product I should mention is IBM’s Virtualization Manager, which is an extension to IBM Director. The product provides a single console from which users can discover and manage real and virtual systems. Now, the virtual systems would themselves be running virtualization software – and I’ll talk about that layer in a moment.

If you don’t choose IBM, an alternative would be the VMware’s product suite, which comprises eight components: Consolidated Backup (for backing up virtual machines), DRS (for resource allocation and balancing), ESX Server, High Availability (an HA engine), Virtual SMP (offering multiprocessor support for virtual machines), VirtualCenter (where management, automation, and optimization occur), VMFS (a FileSystem for storage virtualization), and VMotion (for migration).

Also, quite well-known is HP’s ProLiant Essentials Virtual Machine Management Pack, which more-or-less explains what it does in the title.

Lastly, for this list of management software are CiRBA’s Data Center Intelligence (now at Version 4.2) and Marathon Technologies’ everRun. Marathon also has its v-Available initiative.

In terms of software that actually carries out the virtualization on an x86 platform perhaps the two best-known vendors would be VMware and XenSource. VMware has its ESX Server (mentioned above) and XenSource has XenEnterprise, XenServer, and XenExpress.

VMware’s ESX Server reckons to have around 50% of the x86 virtualization marketplace. It installs straight on to the hardware and then runs multiple operating systems underneath. The Xen products use the Xen Open Source hypervisor running straight on the hardware and allow Windows and Linux operating systems to run under them. Virtual Iron also uses the Xen hypervisor and is similar to the Xen products. It’s currently at Version 3.7. Also worth a quick mention is SWsoft, who produce Virtuozzo.

One other company that has a small presence in the world of virtualization is Microsoft – you may have heard of them! Microsoft has Virtual Server 2005 R2, which, as yet, hasn’t made a big impact on the world of virtualization.

So, any virtualization beginners out there – I hope that helped.

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