Ceph is a unified storage solution

Unified storage from a storage vendor's perspective is defined as file-based Network-Attached Storage (NAS) and block-based Storage Area Network(SAN) access from a single platform. NAS and SAN technologies became popular in the late 1990's and early 2000's, but when we look to the future are we sure that traditional, proprietary NAS and SAN technologies can manage storage needs 50 years down the line? Do they have what it takes to handle exabytes of data?

With Ceph, the term unified storage means much more than just what traditional storage vendors claim to provide. Ceph is designed from the ground up to be future-ready; its building blocks are scalable to handle enormous amounts of data and the open source model ensures that we are not bound to the whim or fortunes of any single vendor. Ceph is a true unified storage solution that provides block, file, and object services from a single unified software defined backend. Object storage is a better fit for today's mix of unstructured data strategies than are blocks and files. Access is through a well-defined RESTful network interface, freeing application architects and software engineers from the nuances and vagaries of operating system kernels and filesystems. Moreover, object-backed applications scale readily by freeing users from managing the limits of discrete-sized block volumes. Block volumes can sometimes be expanded in-place, but this rarely a simple, fast, or non-disruptive operation. Applications can be written to access multiple volumes, either natively or through layers such as the Linux LVM (Logical Volume Manager), but these also can be awkward to manage and scaling can still be painful. Object storage from the client perspective does not require management of fixed-size volumes or devices.

Rather than managing the complexity blocks and files behind the scenes, Ceph manages low-level RADOS objects and defines block- and file-based storage on top of them. If you think of a traditional file-based storage system, files are addressed via a directory and file path, and in a similar way, objects in Ceph are addressed by a unique identifier and are stored in a flat namespace.