Remus and Kemari, the 2 VM mirroring solutions for Xen both made some announcements recently.
Remus announced the availability of version 0.9 this release is build against the tip of the xen-unstable repository, and supports PV and HVM in 32-on-32, 64-on-64, 32-on-64, and 64-on-32 configurations. It has been tested using Linux (Ubuntu) PV guests, and both Linux and Windows XP under HVM.
According to the Remus website Last week Remus has been applied to the official Xen repository and is expected to be i
ncluded with the next major release.
In case you forgot Remus provides comprehensive fault tolerance for Xen virtual machines. If the physical machine hosting your VM fails, the backup can take over instantly, as if you had migrated it to the backup at the instant before the failure occured. There’s no need for recovery, because the backup is always completely up to date. Furthermore, Remus runs completely transparently, requiring no changes to your existing guests.
Kemari, the other fault tolerance solution for Xen however announced that the in
itial work for porting Kemari to KVM has started .
The basic design for Kemari for KVM is ready and they have send out a RFC to get early feedback , the full RFC announcement by Fernando Luis Vázquez Cao can be found on the Linux KVM mailing list
More info on Kemari is available on their website