We just bought a new server with the following specs:

Dell Poweredge T300
1 x Intel Xeon X3323 Quad Core 2.5 ghz
16 GB Ram

We need to run aprox. 12 virtual machines on this server:

1 CentOS (SAMBA)
1 CentOS (DNS - Bind)
2 CentOS (MySQL)
6 CentOS (Apache)
1 WinXP IE6 (for VNC access to perform testing)
1 WinXP IE7 (for VNC access to perform testing)

All of them will be used very "lightly". All of them are intended for web app development and testing among a group of 6 programers so no heavy duty use on any of them.

We are replacing an aging Dell Poweredge 2600 with 512MB ram (that's right) with an intel xeon processor (single core 1.8Ghz i believe)
It was running Open Virtuozzo and did managed to run aproximatelly 10 virtual servers (yes.. i know..) all of them running at the same time on only 512 MB RAM.

So.. we are still deciding on which technology to use. Did we mention that we need them to be free options?

So far we've narrowed it down to 4 contenders:

• Xen 3.0.3 (CentOS native virtualization technology)
• VirtualBox 2.2
• VMware ESXi
• VMware Server 2

Anyone with experience running this many servers in a single server using the above listed technologies?

We haven't been able to find any recent comparisons among them (only a few old blog posts here and there but all talk about outdated versions).

Any suggestions?

If this is intended for a production environment, I would strongly urge you to evaluate VMware ESX server: despite its expense. If you need it (and it sounds like you might), it's definitely worth it.

Evaluating ESX Server would also provide a good benchmark against which you can evaluate the other contenders.

IMHO .. PSM

PS:
There's probably no "one-size-fits-all" solution, probably no unequivocably "right" answer. It would be wise to evaluate several alternatives, and see what works best for you.

VMware Server is out. It only allows you to use 2 CPUs.

XEN Might not work with multiple OSes. I believe it is a shared kernel.

VMware ESXi might be a good one to give a whirl. Its free, so why not? Just make sure your RAID Controller is compatible.

Honestly, I don't know why you need all these different machines to do simple tasks. Thats what multiple services are for but that is for a different thread itself.

VirtualBox might also be a good decision. You install your base OS and run things fully virtualized in a fairly light hypervisor. It also has the option to run headless. Virtualbox.org for more info.

I use Virtualbox so I can still use windows for AD Stuff (Sorry Linux, its just much easier already being authenticated against the domain).

ESX or Vbox Definitely. ESXi you might find to be much more expert-level. Vbox is kinda dulled down to make things really simple to setup and go. ESX Might cause several sleepless / codeless nights while you struggle to get a hold of things.

------------------------------------
Michael Piekarski
Network Engineer
mpiekarski@hostmysite.com
www.hostmysite.com

thanks mpiekarski for you input.

We did in fact select virtualbox.

We first tried using CentOS builtin virtualization solution (Xen) and worked great until we reached 4 virtual machines. After 8 minutes of running the 4th concurrent VM, the host server simply crashed. Tried it on three different servers and all had the same problem. We didn't feel like spending a lot of time debugging xen in order to get them running so.. we opted for a different solution.

So, after carefull study, reviewing experiences by peers, etc.. we tried out virtualbox. It is indeed a great solution. We were able to run 13 VM at the same time without any problem.

My only concern right now is the Oracle - Sun deal. Sun has a lot of very interesting technologies under its umbrella (MySQL, Virtualbox, OpenOffice, etc). Im not sure if Oracle is indeed interested in those technologies.

We use all this different VMs to "replicate" our production environment. We need to have an "almost" identical replica of our production systems in order to make sure the entire setup works. In order to squeeze every possible bit of permormance to each physical server, we tweak every aspect of the system. Most of them don't even run sendmail or serveral "default" services.

We all code in Mac OS machines, but in order to test our web systems we need to test on Windows how they look. The fact that there are now three major IEs out there (IE6, IE7, & IE8). Running them locally at the same time in our development machines will mean that we run have to run at least three VMs at that slows down our Mac OS machines. (Don't get me wrong here, they are perfect capable of running any VM, but in order to test CSS & Javascript, we do need to test on all IE flavours - damn IE6!!).

So, Virtualbox has this nice VRDP feature that simply allows you to "use" any VM running on a server as if it was actually on your desktop computer. For Mac OS we found "CoRD" app to be a nice solution.

One other thing that Virtualbox has is the ability to use the same exact VM on a different host machine. You just simply copy and paste the virtual hard drive and off you go.