Learning Ceph - Second Edition

Object Storage Daemons (OSDs)

OSDs provide bulk storage of all user data within Ceph. Strictly speaking, an OSD is the operating system process (ceph-osd) running on a storage host that manages data reads, writes, and integrity. In practice, however, OSD is also used to refer to the underlying collection of data, the object storage device, that a given OSD manages. As the two are intimately linked, one can also quite reasonably think of an OSD as the logical combination of the process and underlying storage. At times, one may see OSD also used to refer to the entire server/host that houses these processes and data, though it is much better practice to refer to the server/host as an OSD node that houses as many as dozens of individual OSDs. ...