Oracle VM, VMWare, Solaris logical domains (ldoms) and Containers, Xen, Hypervisors are all terms that relate to virtualisation, but what actually is it?

With any server, you install the software you want to run. If it’s not being used to its full potential, the hardware is underutilised. Virtualisation harnesses the underutilised resources in your hardware by allowing you to run many ‘virtual servers’ on the same piece of hardware. This translates into less physical servers and a greater return on investment for the business, i.e. you’re getting more for less! By controlling the physical resources available for each environment, you can have your cake and eat it!

With hardware becoming ever more powerful, organisations are realising that more efficient use of resources can be made by running lots of virtual servers on one physical server. These virtual servers are, typically, self-contained environments running their own operating systems. One could be Redhat Linux, one could be Windows Server 2008 while another could be Oracle's Unbreakable Linux.

Which one should we use?
Tough question at the moment! Most vendors are producing solutions based on Xen technology. So far this has been implemented as Oracle VM (Virtual Manager), Redhat, SUSE, Citrix Xensource, Sun local domains and Windows 2008. VMWare’s ESX server remains the most popular as its been around the longest. BUT .... ask a few questions ..... How does the performance compare? Are the applications and databases supported in virtual environments? Is the virtualisation software proprietary? Who is backing the ongoing development?

How can we get started with Virtualisation?
There are many articles on the web that will help get you started:- Alternatively, e-DBA has implemented virtual environments based on Oracle’s Unbreakable Linux, Oracle VM, Redhat Linux and Solaris logical domains and containers.

What about Oracle Database Support in virtual environments?
One important point to make is that Oracle databases are currently only officially supported on Oracle VM. This means that if you are on an alternative virtualisation technology, Oracle will provide support if the issue is known ... otherwise you need to replicate the problem in a bare metal environment, i.e. no virtualisation.