I’ve been feeling less than thrilled with the open source virtualization alternatives available. It’s not that I am not grateful for all the hard work people have put into these systems. I am increasingly finding the platforms to be buggy. I’m trying to decide on what the best setup is moving forward. Just thought I would jot down some of my recent notes.
As someone that prefers Debian and Debian-based distros using Xen means using Debian. However the Xen 4.0.1 packages in Debian Squeeze have seemed buggy to me, partcularly when allocating large amounts of memory to a DomU. In addition for the purpose of running a Windows server there are no signed paravirtualization drivers available. This leaves people in the position of choosing lower performance or the hassle of unsigned drivers. Those drivers can be found at http://www.meadowcourt.org/downloads/. The Xen team has had some recent success getting parts of the dom0 kernel code merged. If the entire
I have generally believed that KVM would overtake Xen given the level of development activity. Yet, in my dealings with KVM I still find it has a long way to go. I find bugs with virtual machines using SMP (performance problems, lockups on AMD processors) and even keeping a correct clock for Windows systems. There are signed Windows drivers but the virtio net drivers are too buggy for production use (as of version 1.1.6). You can get those drivers here: http://alt.fedoraproject.org/pub/alt/virtio-win/latest/images/bin/. KVM is so well supported that there are many OS options: Debian, Ubuntu, Proxmox.
OpenVZ / LXC
I used linux-vservers for quite some time before switching to Xen. Container-based virtualization is seeming better to me now in that performance should be close to native, particularly with regard to latency. I also think I overlooked the value of container-based virtualization with regard to ease of management tasks such as backup or migration. I haven’t used OpenVZ or LXC. Using Proxmox to administer OpenVZ seems like it might be a pretty easy way to go. OpenVZ can also be used from Debian.
- Debian 6 – Xen, KVM, OpenVZ
- Ubuntu 10.04 – KVM
- Proxmox – KVM, OpenVZ
- – unsigned paravirtualization drivers
- – buggy with large memory
- + signed paravirtualization drivers
- – buggy paravirtualization nic driver
- – clock issues
- – SMP issues
- + ksmd may offer more memory for virtual servers