Hi all,

So I've decided that the best way for me to sort out my new server is to install a base OS, which I will secure, and then set up Virtualmachines using KVM or Virtualbox to run on top with a media server, mail server etc.

For the base, I was looking at a good distro that is solid and can be updated for years. I had kind of settled on Debian or Centos, sensible server choices. However, I noticed that Centos is still on the 2.6 versions of the kernel, and Debian was 3.2.

Would I lose much going with Centos?

Is Debian easy to upgrade to the next stable release? Basically I want something to run for years as a base, and I can tinker with the VMs which will be other Os's.

Also, does KVM have advantages over virtualbox for this?

Thanks

Note that Red Hat will be releasing RHEL 7 (cuerrently in beta) within the next few months, meaning CentOS 7 will not be far behind , which will then mean CentOS will be ahead of Debian stable. I've run VM hosts on both CentOS 6 and Debian stable, and I haven't noticed too much of a difference in terms of feature sets. There are a couple of virtual CPU types missing from the older version, but it's never really caused me any problems.

I've installed a few test systems from squeeze to wheezy (and done older upgrades too). I can't recall any major issues, but IMO the safest thing to do is reinstall. Since you're running VMs, this is easy; just back up the virtual disk images (which you should be doing anyway), reinstall the new version, and copy back the virtual disks. FWIW, CentOS strongly recommends a reinstall between major versions, though it's theoretically possible to do it "on the fly."

I like KVM because of the good command line tools for VM management, snapshotting, etc. But I'm not very familiar with VirtualBox, so I don't kbnow if it offers anything similar. I'll let someone more savvy with hypervisors handle this one.

only kvm!

VirtualBox has good commandline tools as well, quite comparable to virsh and friends. The main tool is vboxmanage; it allows starting, stopping, controlling a running VM in various ways, taking snapshots, creating networks, disks, ... Having said that, KVM is a RedHat product, and if you use Centos or RedHat anyway, it's a natural choice.

If you don't need support for 3D acceleration I would go for KVM every time. It is easy to manage, especially using tools like VirtManager and as benchmarks show has better performance than Virtualbox. Nowadays I don't use Virtualbox anymore, just KVM for VMs without needs for 3D, VMware Player for VMs that need 3D.