Distributed Replicated Block Device

DRBD^® software is a distributed replicated storage system for the Linux platform. It is implemented as several userspace management applications and some shell scripts and is normally used on high availability (HA) computer clusters.

DRBD also refers to the logical block devices provided by the scheme and to the software that implements it. DRBD device and DRBD block device are also often used for the former.

The DRBD software is free software released under the terms of the GNU General Public License version 2.

DRBD is part of the Lisog open source stack initiative.

Mode of operation

DRBD layers logical block devices (conventionally named /dev/drbdX, where X is the device minor number) over existing local block devices on participating cluster nodes. Writes to the primary node are transferred to the lower-level block device and simultaneously propagated to the secondary node. The secondary node then transfers data to its corresponding lower-level block device. All read I/O is performed locally.