drbd (Distributed Replicated Block Device)

DRBD is a block device which is designed to build high availability
clusters. This is done by mirroring a whole block device via
(a dedicated) network. You could see it as a network RAID1. DRBD
takes over the data, writes it to the local disk and sends it to
the other host. On the other host, it takes it to the disk there.

This package contains the userspace tools for drbd.