Highly Available STorage
Highly Available Storage is a protocol and tool set for FreeBSD written by Pawel Jakub Dawidek, a core FreeBSD developer.
HAST provides a block device to be synchronized between two servers for use as a filesystem. The two machines comprise a cluster, where each machine is a cluster node. HAST uses a Primary-Secondary configuration, so only one cluster node is active at a time.
HAST-provided devices appear like disk devices in the /dev/hast/ directory in FreeBSD, and can be used like standard block devices. HAST is similar to a RAID1 where each RAID component is provided across the network by one cluster node.
