VMWare

[Chetan Parekh]

Does VMWare comes with preinstalled Linux of any flavor ?

[Terry Rappatillo]

Hello,

Originally posted by Chetan Parekh:
Does VMWare comes with preinstalled Linux of any flavor ?

What do you mean with pre-installed linux? VMWare workstation and VMWare GSX server products runs on top of linux or windows just like any other regular application so they require linux to be installed before being able to install VMWare. VMWare ESX server makes an exception: it doesn't require any pre-installed O/S as it implements own O/S like platform for running virtual machines.

I guess you meant whether VMWare's got to offer a pre-configured linux-based guest machine? There are quite many vendors out there providing virtual machines for different kind of purposes. Please see Virtual Machine Center for more information. At the time of writing this, there're prebuilt virtual machines for Red Hat, SuSe and Ubuntu linux.

HTH, Tero

[Stan James]

I was reading about Xen just before I read this. Free, Intel based, runs many different OSs (at the same time!) on top of the VM. Robust enough for hosting sites that let you run anything you like on your virtual server.

[Terry Rappatillo]

Originally posted by Stan James:
I was reading about Xen just before I read this. Free, Intel based, runs many different OSs (at the same time!) on top of the VM. Robust enough for hosting sites that let you run anything you like on your virtual server.

There's also a commercial product that bases on same techniques than Xen: Virtuozzo.

Here's a short comparison of the virtualization techniques used in Xen, Virtuozzo and VMWare.

Xen and Virtuozzo both virtualizes the host O/S by partitioning it as separate independent nodes. This means that these guest machines needs to run same O/S than the computer running virtualization software: linux on linux-based host and windows on windows-based host. In some situations this is very desired. With approach like this, one can achieve lower virtualization overhead. Guest machines supports same devices etc. than the host O/S.

VMWare (Workstation and GSX Server) instantiates a copy of the hardware of the actual physical machine for each virtual machine a.k.a. guest machine running on the computer. This generates larger virtualization overhead, but makes it possible to use different operating systems in both host and virtual machines. Guest machines supports devices that VMWare supports.

[Stan James]

I'm a total novice in this area (except for 20 years on IBM's mainframe VM) but this bit:

Xen and Virtuozzo both virtualizes the host O/S by partitioning it as separate independent nodes. This means that these guest machines needs to run same O/S than the computer running virtualization software: linux on linux-based host and windows on windows-based host.

didn't seem to match what Xen claims. They say that future versions of Windows may have hooks that will let Xen run them. I skimmed a Xen architecture whitepaper and it seems to require more OS level customization than VMWare and interestingly works more easily on Intel.

I got interested in virtualization when I saw that Xen is used in hosting sites. One can have full control of a virtual Linux server pretty cheaply. I could convert some of my sites from ASP to Servlet and save money.

[Terry Rappatillo]

Originally posted by Stan James:
[QB]I'm a total novice in this area (except for 20 years on IBM's mainframe VM) but this bit:

didn't seem to match what Xen claims. They say that future versions of Windows may have hooks that will let Xen run them. I skimmed a Xen architecture whitepaper and it seems to require more OS level customization than VMWare and interestingly works more easily on Intel.

Ah, sorry. It's been a while I've checked Xen's web pages last time and this windows support seems to be quite fresh thing.

[Robert Hayes]

Is anyone aware of any issues or potential pitfalls when using VMWare with application servers or databases?

So far our experience with it at work hasn't been that great for certain types of servers...