DRBD® refers to block devices designed as a building block to form high availability (HA) clusters. This is done by mirroring a whole block device via an assigned network. DRBD can be understood as network based raid-1.
In the illustration above, the two orange boxes represent two servers that form an HA cluster. The boxes contain the usual components of a Linux™ kernel: file system, buffer cache, disk scheduler, disk drivers, TCP/IP stack and network interface card (NIC) driver. The black arrows illustrate the flow of data between these components.
The orange arrows show the flow of data, as DRBD mirrors the data of a high availably service from the active node of the HA cluster to the standby node of the HA cluster.
The "International Journal of Critical Computer-Based Systems" (IJCCBS) is a quarterly research journal by Inderscience Publishers. It focuses on engineering and verification of complex computer-based systems (where complex means large, distributed and heterogeneous) in critical applications, with special emphasis on model-based approaches and industrial case-studies. Critical computer-based systems include real-time control, fly/brake-by-wire, on-line transactional and web servers, biomedical apparels, networked devices for telecommunications, environmental monitoring, infrastructure protection, etc.