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<< Part 4 Xen Overview

1. 1. Virtuozzo.
      1. Guest OS’s Supported. |outline
      2. Driver’s Support. |outline
      3. Speed of Guest OS. |outline
      4. Ease of Management. |outline
      5. Support.
      6. Virtuozzo Summary. |outline

Virtuozzo.

Virtuozzo is a product developed by Parallels Inc., and is an OS virtualization software. This means that it differs from a product like Xen in two important ways:

1. It is proprietary, and therefore closed source and not free.

2. It is more like a Type II Virtualization software (though not quite) as opposed to Xen, which is a Type I.

The technical term to describe Virtuozzo’s technology is Operating System-level virtualization.

Guest OS’s Supported.

This is the biggest limitation of Virtuozzo. It is also it’s biggest strength. Due to it’s very nature as an Operating System-level Virtualization implementation, Virtuozzo runs on top of a standard OS instead of directly on top of the hardware. This means that it can only host guest OS’s that are the same as the OS on which it is running. Let us understand this a bit more.

Virtuozzo isn’t a “true” virtualization software at all. While it does allow various instances of a guest OS to run, in reality, they are other instances of the main OS. That is why you cannot have a Guest OS that is different from the Main OS.

How does this matter? Well, there are several implications, not the least of which is licensing issues. Till just a little while back, Microsoft’s license agreement was such, that if you were running 7 instances of Windows Server on Virtuozzo (Which in turn was running on a main Windows Server OS), you would need to buy just one license, whereas you would have to buy eight licenses if you were running a full virtualization solution like Xen.

Microsoft has since updated it’s licensing agreement, and you can now run upto four instances of a Windows Server with just one license. Still, it’s quite a cost saving over a Hypervisor.

Other implications are that it’s easier to manage. If you have to apply a security update, you just need to install it on the Main OS and not individually on all 7 guest OS’s.

Of course as mentioned earlier, unlike a hypervisor, you are limited to guest OS’s that are the same as that on which Virtuozzo runs. That currently includes Windows Server 2003 and most Linux Distributions.

Driver’s Support.

This isn’t at all an issue with Virtuozzo. If you have drivers for your hardware on the Main OS  (which you probably will) on which Virtuozzo runs, you will have no issues with drivers for your guest OS’s, since they are just instances of the main OS.

Speed of Guest OS.

There’s no doubt that Virtuozzo runs very fast. Much faster than a hypervisor would since there is only one instance of the kernel running. In fact, the overhead for the guest OS is usually just between 1-3%

Ease of Management.

Since Virtuozzo is an Operating System-level virtualization implementation, the management is inherently simpler. In addition, Virtuozzo comes with a suite of management tools that assist the administrator in carrying out all the important task associated with OS virtualization.

Support.

As Virtuozzo is a piece of commercial software, support is extensive. Various plans can be purchased from Parallels Inc. 30 days of installation support is provided with every purchase of Virtuozzo, as well as a software maintenance agreement for the first year. In addition, Virtuozzo provides training courses for your staff for their products.

Overall, if you want to go Enterprise with Virtuozzo, you will be able to get all the back up you need.

Virtuozzo Summary.

For all the benefits of Virtuozzo, the only price that you pay is the lack of flexibility of being able to run whatever OS’s you want. Also, if there is an issue like a kernel crash of the main OS, then the whole system goes down.

However, several users look on the ability to run multiple instances of an OS as an advantage. It makes management simpler, and can reduce licensing costs.

>> Next Part 6 Microsoft’s Hyper V

This entry was posted on Thursday, November 13th, 2008 at 12:54 pm and is filed under Blog Posts, Server Virtualization. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.