Ceph File System

Ceph File System (CephFS) is a distributed file system that integrates seamlessly with the Ceph storage architecture. By leveraging the Ceph RADOS (Reliable Autonomic Distributed Object Store), CephFS provides a scalable and robust file system interface, adhering to POSIX standards.

Figure 1 illustrates integration of Ceph within the Ceph cluster.

CephFS-based file sharing offers the same desirable features as other storage services on the Ceph platform, including scalability, high availability, and operational efficiency. The following are key Ceph components that enable CephFS to achieve these benefits:

Object Storage Daemons (OSDs)

OSDs are responsible for storing the actual file data in CephFS. Files and directories are represented as objects within RADOS, with OSDs managing data storage, retrieval, and replication to ensure durability and availability.

Ceph Monitors (MONs)

MONs maintain the cluster map and monitor the health of the Ceph cluster. They track the state of OSDs and other components, ensuring operational stability and fault tolerance. For CephFS, MONs facilitate the mapping of file system operations to the underlying object storage.

Ceph Managers (MGRs)

MGRs handle cluster management, monitoring, and administrative tasks. They provide an interface for managing the Ceph cluster and integrate with external services like OpenStack Manila and Kubernetes CSI for additional functionalities.

Ceph Metadata Servers (MDSs)

MDSs manage CephFS metadata, including file and directory operations, access control, and namespace organization. They coordinate with OSDs to ensure consistent and efficient metadata operations.

Scalability

CephFS scales horizontally with the Ceph cluster, allowing for the addition of OSDs, MONs, and MDSs to increase storage capacity and performance, accommodating large data volumes and high client request rates.

Fault tolerance

Inheriting Ceph fault tolerance, CephFS ensures data durability and availability through replication and erasure coding provided by RADOS, even in the event of hardware failures.

Unified storage platform

CephFS integrates with other Ceph storage services such as block storage, object storage, offering a unified platform that simplifies management and supports diverse storage needs.