RFI: Platform Virtualization and Virtual Servers

This post is the second in a series on virtualization: Introduction, Platform (Servers and PCs), Desktop, Application, and Cloud

Platform Virtualization

Of my four rough categories of virtualization, platform or server virtualization is usually what comes to mind first. I use the term platform since this can be done in special situations with PC operating systems, not just server, but I’ll cover those in my next post.
Typically, instead of running a server operating system like Linux or Windows Server on its own hardware, you instead run it inside an already running server. Usually this is done on a special server set up to run many virtual servers on a single box. This can also be done on a PC or laptop, but usually with only one guest operating system running inside the main operating system.

So why would you do this?

  1. Consolidation/Cost: Typical IT datacenters have many, many servers but many of those servers don’t work very hard. There’s lots of spare processing cycles to go around. Consolidation of these servers into less physical boxes saves hardware cost, power, and space. In large datacenters this can add up to huge cost savings for a company, if the profile of the servers being consolidated is right.
  2. Flexibility/Dynamic Capacity: Sometimes servers don’t need to be around all that often. A company may need to add capacity only occasionally (like during tax season) or may keep special application servers around only for particular projects. Virtual servers can be moved around much more easily than physical servers and can be stored as images in large data storage. Some companies keep a virtual library of special use server images that can be set up when needed.
  3. Development/Testing/Support: Sometimes a PC user may have a need for a special use operating system on their own PC. I’ve done this often for demo purposes, even running a virtual server OS on my laptop at times to show of some scenario or capability. This is also often used to host special development or testing environments. Finally, some critical or interesting pieces of software may not run on your main operating system and so a virtual guest environment may be useful (e.g. Windows on a Mac or Linux on a Windows PC.)

Server Virtualization – Industry Roundup

Here’s a rundown of some of the main players in platform virtualization and a high-level analysis of each:

Citrix – XenServer 
EMC – VMWare
IBM – z/VM Microsoft – Hyper-V
Open Source – Xen 

Oracle – VM Server
With that roundup I’ll break for now and cover PC level platform virtualization in my next post. Until then let me know if you have any comments or see any gaps. Enjoy!