Hy, I got a brand new Intel i7 Server-System with 12GB Ram and I want to consolidate three other linux-servers onto this machine using virtualization. I want to use the harddisks (via a kind of LVM) in the server as storage as I got no SAN/IScsi. All Linux-VM's will run Debian-Linux, so no need for Windows-Support. I would prefer a bare-metal-virtualization (so where I dont have to maintain the os of "dom0"). The software should be free, even better open-source.

The virtual machines will run: PostgresSQL, a Lighttpd+PHP, a Tomcat-Server, a Mail-Server, a static-files Lighttpd.

The problem is, I cant decide which system to choose:

VMware EsXi: The Problem is the unsupported NIC in the server: It is a realtek-chip and as it is a hosted server I cant modifiy the hardware.

Citrix XenServer: I need the mangment Software to run under Linux, the Citrix-Software only runs on Windows. Bigger problem: You cant store the machines on the internal harddisk, you need a SAN.

XEN: Currently my favorite, but I found no managment software to use for showing the status of the virtual machines. I would have to setup a debian-system as dom0 and maintain it.

OpenVZ: I hate this, it never worked under debian right the way.

Main Problem is: the market is changing fast, so whatever I found on the internet was somehow outdated, so can anybody give me some advices? Thanks!

  • 4
    You are mistaken about XenServer and local, internal disk. XenServer works with it just fine.
    – ktower
    Jan 5, 2010 at 14:47
  • openxenmanager: GUI for XenServer and XenCloudPlatform.... works on Linux too!
    – JMS77
    Nov 2, 2011 at 16:54

14 Answers 14


Have you considered KVM?


Maybe not the most popular answer, but if you love XEN, go with it. You probably know it best, are most familiar with using it, and you can use a mix of SNMP tools and monitoring agents to get a good idea of system status and performance. Why go with another solution if you have one you like and know you can work with?

My personal favorite inclination is ESXi which you said you can't use due to hardware. But that's because I'm most familiar with that solution :-)


You will always have to update some OS or virtualization platform, called dom0 or something else, no matter what you choose. You do not seriously think ESX is without updates?

Given the choices and the OS in the VM's, I'd go for building a CentOS server as a Xen dom0 and then run the Debian domU's on it. CentOS will provide nice management tools, through GUI or console and is free in all the different meanings of the word.

As for the other options: ESX GUI management tools require Windows as well and Citrix is not what I would call a star on the Xen firmament. I don't know OpenVZ enough to say something useful about it.

As I always say at questions like this one: consider CentOS 5.4 and up with KVM, which is the future for Linux as a virtualization platform (and by that I mean that Xen probably is not, in the long run, as Red Hat will drop it from RHEL6).


definitely KVM. Not only is it the true Linux hypervisor, but it's also the one most developed by Red Hat, who are known to be a major code contributor.

Since all you have is a single host, I wouldn't suggest you go with RHEV, but kvm is definitely the best choice in your case


I would go with Xen. For monitoring you could use Nagios which has plugins for Xen monitoring, though this won't help you with VM management.
I run CentOS and there is Virtual Manager which is from RedHat.

I found what looks like a Debian port here


I do not recommend Xen Center at all ! I've a lot of experience on it and with high load I can confirm it doesn't work very well.

In addition of that, too many multiple networks connections can be dropped.

Xen open source is a good solution, but I didn't try it in production use.

You forgot a solution : KVM. I strongly suggest it ! I've red some news on internet relating the possibility of Xen source being deprecated because of Citrix choices.

As KVM is embedded in kernel and a big community is around it, I suggest it :-). I use it today in production and I'm happy with that. You can use is has disk image or LVM like you wish.

I like OpenVZ too, but for your needs and what you've asked, I think KVM is your solution !

  • What do you use for KVM management? I'm not liking virt-manager that much. Sep 28, 2011 at 20:05

for xen and kvm you can use convirture.com tool call convirt good one


We have used XenServer for a year. Yes the GUI management tool is Windows only, but the command line tools are all there just like straight Xen. We are running multiple servers, several under heavy load, no problem. With one host, the free version would work very well. As far as Nagios goes, it has very limited Xen monitoring capability, close to none. We monitor the VMs and the hardware host seperately. With the ability to move VMs from host to host, it's hard to monitor VMs with the Nagios architecture. We are running all CentOS VMs.


Whichever virtualization software you decide to go with why not check out openQRM for your VM management tool?

a. Let's you manage Xen, KVM and ESX/i servers and VM's
b. Web-based gui for ease of use with a pretty slick interface
c. You can install it from either source or as a .deb for Debian/Ubuntu
d. Can manage VM's kept locally or on an network storage device (accessible via NFS, iSCSI, etc)

I have just recently started using it myself but the product appears to be very well done.

Oh, did I mention that there is both Nagios and Puppet integration out of the box? How cool (and useful) is that! Below is a "how-to" PDF document that I found useful when I started 'playing' with openQRM. Good luck!





While openvz and Vserver are very fine, LXC, along its maturity evolution, becomes a more attractive choice on several levels. Its support should come into proxmox release 2 by the way.


Xenserver can run on a local harddisk, it does not need SAN. However KVM is also an option. The question is, what do you need ? I really like KVM, I prefer it even over Xen. However templating like you can do on Xen isn't there yet.

Nothing impedes you from using cmd on Citrix Xenserver, it is quite easy.


I've been using KVM for about a month on my new laptop and like it a lot. At work we run Xen on CentOS in production and feature wise they are very similar. But KVM seems to be pretty solid and has a much more active community behind it so in some ways it's already surpassing Xen's features. And I expect this gap to widen further with time.

So far I must say that I do prefer the network scripts from Xen over the KVM stuff though. I've found that if you want a VM on your local subnet via bridging you really have to jump through more manual hoops to create the TAP devices and setup the bridge. Where the Xen scripts handle this pretty well.

But if you don't need any windows support OpenVZ may be a pretty good solution. It's similar to Solaris Zones and BSD Containers so it's not really "Virtualization". But it also doesn't have some of the IO and hard provisioning issues that Virtualization has. Under OpenVZ each VM can have guaranteed resources: ram, cpu, etc...similar to giving a VM ram and vcpu's. But in addition to this each VM can also utilize all the available resources if the other VM's aren't using their guaranteed resources. Which means if you have 10 VMs and 9 of them are idle the one that needs the cpu power can utilize the full processing power of the i7.


How about Linux-VServer? http://linux-vserver.org/Welcome_to_Linux-VServer.org

It is something like OpenVZ but with support for current kernels (OpenVZ is focused on RHEL5 so it is hard to use it with current kernel)

OpenVZ and VServer are better than other because you don't have performance penalty like in "real" virtualization solutions.


Your specific software requirements for your VM's,are pretty basic. Go with simplicity. Use OpenVZ. I do not know what your specific problem(s) was with DEBIAN and OVZ,as I have tested OpenVZ on both REDHAT,and DEBIAN. I just do not like DEBIAN as a mainstream LINUX,regardless of whether I need simple servers,or enterprise level. KVM,is nothing more than kernel-level QEMU,which makes for light PC emulation. Unless I was contemplating heavier software requirements down the road,I would go with OpenVZ. You want DEBIAN for a VM base server,go with Proxmox. You want REDHAT for a VM base server,choose OpenNode.(x86_64 and free). Supports both KVM and OpenVZ. Has its own management interface. You decide to use XEN and LINUX ver.X,there is a GUI management console interface for XEN,called OpenXENManager. Why piece it this together,when you can run Oracle Enterprise Server and Oracle VM.

Good luck.

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