Ceph

Ceph
Name	Ceph
Developer	Sage Weil; Red Hat
Released	2006
Programming language	C++, Python
Operating system	Linux
License	LGPL

Ceph Ceph is a distributed storage platform designed for object, block, and file storage. It provides unified storage via software components that run on commodity Linux, leveraging algorithms from distributed systems research developed by contributors associated with University of California, Santa Cruz, Sage Weil, and commercial engineering teams such as Red Hat and other vendors. Ceph is used by organizations including CERN, Wikimedia Foundation, Yahoo!, and cloud providers to deliver resilient storage for large-scale infrastructure.

Overview

Ceph delivers object storage through the RADOS layer, block storage via RBD, and a POSIX-compliant file system via CephFS. The project originated from research at University of California, Santa Cruz and has been adopted by enterprises and projects including OpenStack, Kubernetes, Proxmox VE, SUSE, Canonical, Amazon Web Services integrators, and academic labs such as Lawrence Livermore National Laboratory. Key concepts include CRUSH maps, placement groups, and monitors; these concepts are implemented in daemons like OSDs, monitors, and MDS servers that interact with tools such as Cephadm and orchestration platforms like Ansible and Terraform.

Architecture

Ceph's architecture centers on the reliable autonomous distributed object store called RADOS, which uses the CRUSH algorithm originally described by researchers linked to Sage Weil and others at University of California, Santa Cruz. The design incorporates OSD daemons for object storage, MON daemons for cluster consensus, and MDS daemons for metadata management in the filesystem layer; these components are commonly deployed on Linux distributions such as Red Hat Enterprise Linux, Debian, Ubuntu, CentOS, and SUSE Linux Enterprise Server. Ceph supports replication and erasure coding controlled by the CRUSH map and pg-placement which can be tuned for topologies like racks, rows, and datacenters familiar to operators from Facebook, Google, Microsoft Azure, and Twitter infrastructures. Networking for Ceph often leverages technologies from Mellanox Technologies (now part of NVIDIA), standards like RDMA, and protocols such as RADOS Gateway that expose S3 and Swift-compatible interfaces used by OpenStack Swift clients and Amazon S3-compatible tools.

Deployment and Management

Deployments range from single-site clusters to geographically distributed setups using multisite synchronization and tools such as Ceph RADOS Gateway (RGW) multisite. Operators orchestrate clusters using ceph-deploy, ceph-ansible, Cephadm, or custom automation via Kubernetes Operators and configuration management systems like Puppet and SaltStack. Monitoring integrates with telemetry and observability stacks including Prometheus, Grafana, ELK Stack, and Nagios; backup and recovery workflows interoperate with backup solutions from vendors like Veeam and Commvault. Integration testing and CI pipelines for Ceph development commonly use systems like Jenkins, GitLab CI, and continuous integration infrastructures used by projects such as Linux Foundation initiatives.

Performance and Scalability

Ceph scales horizontally by adding OSDs and adjusting CRUSH rules; large deployments at facilities such as CERN and cloud providers demonstrate petabyte-scale clusters. Performance tuning touches on disks (SSDs, NVMe), caching layers (tiering), and network fabrics (10GbE, 25GbE, 40GbE, 100GbE) provided by vendors like Intel, Broadcom, and Mellanox Technologies. Ceph's erasure coding capabilities trade storage efficiency for CPU and network overhead; benchmarks often reference tools and suites from FIO, RADOS bench, and industry testing by SPEC-affiliated labs. Scalability characteristics are affected by metadata operations in CephFS, making MDS design and placement important; projects such as OpenIO and GlusterFS provide alternate architectural comparisons.

Use Cases and Integrations

Ceph supports block storage for hypervisors and platforms including KVM, QEMU, Xen Project, and VMware integrations, and object storage for applications that expect Amazon S3 semantics. It is used for backends in OpenStack Cinder and OpenStack Swift deployments, as storage for Kubernetes persistent volumes via CSI drivers, and in scientific computing pipelines at institutions like Los Alamos National Laboratory and Oak Ridge National Laboratory. CephFS serves HPC users alongside parallel file systems such as Lustre and BeeGFS in workflows for projects funded by agencies like NSF and DOE.

History and Development

Ceph began as a research project at University of California, Santa Cruz led by Sage Weil and collaborators, later forming the company Inktank which was acquired by Red Hat; development continues with contributions from companies including Intel, Dell EMC, Canonical, SUSE, Huawei Technologies and community contributors coordinated via repositories hosted on GitHub and review systems like Gerrit. The project has evolved through major versions introducing features such as RBD snapshots, BlueStore backend, and cephadm orchestration; these milestones were discussed at conferences including Storage Developer Conference, KubeCon, Cephalocon, and OpenStack Summit.

Security and Reliability

Security in Ceph covers authentication with CephX, integration with identity providers such as FreeIPA, Active Directory, and TLS encryption for cluster traffic; compliance considerations often reference standards from NIST and enterprise practices at organizations like NASA and US Department of Energy. Reliability features include replication, erasure coding, CRUSH-based data placement, and self-healing mechanisms; operational best practices are informed by incident analyses from large deployments at Wikimedia Foundation, Yahoo!, and cloud operators such as Rackspace.

Category:Distributed file systems Category:Storage software