Ceph as file system storage

A file system based storage is like any NAS (network attached storage) system, where the file system is managed by a remote storage device. Ceph uses the Ceph FS (Ceph file system), which provides a POSIXcompliant file system as an interface. A client system can mount this file system and access the file storage.

Ceph FS uses Ceph MDS (Ceph metadata server) in the storage cluster to store the metadata about the file system. This metadata consists of the file system tree structure, timestamps, permissions and other POSIXcompliant data. Ceph MDS can also be distributed by dividing the tree structure and storing it in different Ceph MDSs. This metadata is stored like any other object in the Ceph OSDs, and is replicated for backup and recovery purposes. FreeNAS, NAS4Free are some of the NAS solutions available. The Lustre file system is a famous open source parallel file storage solution. Oracle ZFS Storage and Dell Storage SCv2000 are a few of the popular NAS solutions from proprietary vendors.