Live failover for Xen images

Remus promises to bring to the Xen hypervisor live failovers. In other words, if a host system crashes, another machine picks up the load without any interruption to services.

From the Remus website:

Remus provides transparent, comprehensive high availability to ordinary virtual machines running on the Xen virtual machine monitor. It does this by maintaining a completely up-to-date copy of a running VM on a backup server, which automatically activates if the primary server fails. Key features:

• The backup VM is an exact copy of the primary VM. When failure happens, it continues running on the backup host as if failure had never occurred.


• The backup is completely up-to-date. Even active TCP sessions are maintained without interruption.


• Protection is transparent. Existing guests can be protected without modifying them in any way.

This is neat because the only thing that I know of that provided this functionality is VMWare, which costs big bucks (and still holds the tools advantage). Xen is free, and available for Linux and OpenSolaris.