Server Virtualization

[AnthraxXx]

Hi everyone,

Now, apart from the fact that you can have multiple OS's to run different programs, what else would you use virtualization for?

Like, why use two or more virtual servers on the same machine, assuming they are on the same OS when you could just run them simultaneously without virtualization?

I am confused as wouldn't it be less system intensive to run the software together instead of in different environments?

I hope you guys can understand what I mean, I may even be incorrect/misinformed but I am under this impression after reading the article at HowStuffWorks.

If anything looks weird in this post it's because I did this on my PSP lol.

 

[Ghan]

Virtualization is awesome.

> I am confused as wouldn't it be less system intensive to run the software together instead of in different environments?

Perhaps. However, virtualization allows you to nicely segment different servers that perform different tasks. For example, if your database program goes nuts and crashes, it doesn't necessarily bring down any other programs with it since virtual machines will generally have clearly defined limits on usage. Also, virtualization allows you to only use one physical machine instead of 2, 3, or 4 that you might be using otherwise. So this ability allows you to allocate very specific resources (and change them easily as well) that a particular program virtual machine uses based on what it is doing.

Another good thing about virtualization is that it is much easier to have redundancy and backups. Any decent enterprise solution will usually have some form of snapshot option that can basically create one file out of your virtual machine that contains everything in it, including the OS. This technique can also be applied to easily move virtual machines around to different host machines. Some technologies even allow you to load balance a virtual machine across multiple servers. This means that your one virtual environment is using resources from more than one physical server SIMULTANEOUSLY.
That is also awesome for redundancy. If a server goes down, your virtual machine does not have to do so. It can continue to run on other machines.

Also, if you have something like a NAS (Network Attached Storage), you can, depending on how good it is, setup a connection to multiple virtual machines that essentially act as the virtual machine's hard drives. So all the data can reside on something outside of the server itself, but all the processing still gets done on the physical server.

Further, you don't necessarily know if several programs will all work together on one box. They may have collisions and so on that you didn't expect. And what if you need to do maintenance on some machine? What if you are trying to do updates? You don't want to bring down 10, 20, or 30 different programs that are all trying to run on that server. In a virtual environment, you have a far greater chance of keeping stuff running even during maintenance.

And another thing is development. What if you want a development environment separate from the rest of the stuff? You would normally have to buy another server. With virtualization, you don't have to do that.

So here are a few reasons that virtualization is good from someone who has first-hand experience working in a virtual environment on the enterprise level. Hope this was helpful.

 

[AnthraxXx]

Ok thanks Ghan, that helped a lot!

I read about less physical servers etc in the article but it never really said any more details just how it implements it etc.

But essentially, it's just easier to manage and maintain, right?

So really, you wouldn't need to use Virtualization on a server at home or anything, okay.

I see now why Virtualization would be favoured by larger entities, thanks again!

 

[kingkingyyk3]

So really, you wouldn't need to use Virtualization on a server at home or anything, okay.
Windows XP mode in Windows 7 requires Virtualization, too.