Dennis Krul

Kemari is a virtual machine synchronization mechanism for Xen. It allows you to run a hot standby copy of a virtual machine on a different host. If the active host becomes unavailable for some reason, the standby host takes over without downtime. (Note that this is different from live migration, where both nodes need to be up and running.) This allows for higher availability of your servers. Of course VMware had this feature for some time, but I’m glad someone is working on an open source alternative.

Unfortunately most of the Linux distributions are focusing on KVM instead. For RedHat this makes sense, because they acquired Qumranet (who developed KVM). But Debian and Ubuntu also pretty much gave up on Xen. The only mainstream Linux distribution still actively working on Xen support is SuSE. Actually, the only UNIX based platform that really has good Xen integration is not even Linux based, it’s OpenSolaris, go figure.

I agree that in the long run a Linux kernel based approach to virtualization makes sense, but I also believe today Xen has an edge over KVM and will keep that edge, probably for years to come. Why not bet on both horses and let end users decide which virtualization solution to use?