The Ceph Block Device, formerly known as RADOS Block Device, provides reliable, distributed, and high performance block storage disks to clients. A RADOS block device makes use of the librbd
library and stores a block of data in sequential form striped over multiple OSDs in a Ceph cluster. RBD is backed by the RADOS layer of Ceph, thus every block device is spread over multiple Ceph nodes, delivering high performance and excellent reliability. RBD has native support for Linux kernel, which means that RBD drivers are well integrated with the Linux kernel since past few years. In addition to reliability and performance, RBD also provides enterprise features such as full and incremental snapshots, thin provisioning, copy on write cloning, dynamic resizing, and so on. RBD also supports In-Memory caching, which drastically improves its performance.
The industry leading open source hypervisors, such as KVM and Zen, provide full support to RBD and leverage its features...