Oracle application server
Recently I have gotten a lot of
questions about installing the Application Server instances on virtual machines.
Does Oracle support a production system running of virtual machines? The short
answer is YES. The real question is why? Lets look at some options:
First, Oracle supports it's products on defined operating systems, not the
underlying hardware (in most cases). So if the virtual machine is hosting a
supported OS, then Oracle will support the installation.
Now, lets look at what virtual machines are and what they provide.
What is all this talk of virtualization?
Virtualization is not new. It is another main frame capability that commodity
servers have become powerful enough to implement. In fact, the first Oracle
Application Server I encountered on virtual servers was Oracle9iAS running on
AIX about 3 years ago. In it's simplest form, a virtualization layer is started
below the operating system that "virtualizes" the entire server. Next an
operating system is started and the application runs on the OS. The OS may or
may not know that the hardware it is talking to is virtual. Now the fun part,
you can start as many operating systems as the server can support, and they do
not have to be the same operating system.
Other than the "cool" factor, so what?
Well this is a revolutionary capability when you see that recent surveys
indicate that only 3% of server capacity is being utilized. This number will get
lower as small servers get more and more capability, faster memory, faster CPUs.
So instead of buying six 2 CPU servers and using 3% (I know, you use a lot more)
you can buy one 4 CPU 64bit server with 16G RAM (for less than the six small
servers), virtualized the six servers and save a bundle. One server to maintain,
less heat in the servers room, less electrical load and less UPS requirements.
ALL A BIG WIN FOR THE SERVER ROOM! Of course, then that server fails, all six
virtual servers fail with it.
And there's more!
The virtualization software is available (mostly free) that will run almost any
operating system. VMWARE is the most common I have encountered but with the
release of REDHAT EL 5 any day now, Xen virtualization will also become common.
There are a number of others virtualization software products out there. Some
operating systems like AIX and Solaris have their own virtualization
capabilities. These virtualization layers can control the amount of resources
one virtual machine (operating system) can utilize, such as CPU, memory, etc.
This helps all those different operating systems play well together.
In Part 2 I will discuss the virtualization options available. You can
virtualize the hardware (as discussed above) or you can virtualize the OS using
cartridges or virtualize the application. All have advantages and disadvantages.
In Part 3, I will answer the question of "Why?". There are important
considerations when using virtualization with the Oracle Application Server 10g.