The Ceph Blog

Ceph blog stories provide high-level spotlights on our customers all over the world

  • September 20, 2017
    New in Luminous: Multiple Active Metadata Servers in CephFS

    The Ceph file system (CephFS) is the file storage solution for Ceph. Since the Jewel release it has been deemed stable in configurations using a single active metadata server (with one or more standbys for redundancy). Now in Luminous, multiple active metadata servers configurations are stable and ready for deployment! This allows the CephFS metadata …Read more

  • December 5, 2013
    Ceph Storage :: Introduction


    What is CEPH

    Ceph is an open-source, massively scalable, software-defined storage system which provides object, block and file system storage from a single clustered platform. Ceph’s main goals is to be completely distributed without a single point of failure, scalable to the exabyte level, and freely-available. The data is replicated, making it fault tolerant. Ceph software runs on commodity hardware. The system is designed to be both self-healing and self-managing and self awesome 🙂


    CEPH Internals

    • OSD: A Object Storage Daemon (OSD) stores data, handles data replication, recovery, backfilling, rebalancing, and provides some monitoring information to Ceph Monitors by checking other Ceph OSD Daemons for a heartbeat. A Ceph Storage Cluster requires at least two Ceph OSD Daemons to achieve an active + clean state when the cluster makes two copies of your data . 
    • Monitor: A Ceph Monitor maintains maps of the cluster state, including the monitor map, the OSD map, the Placement Group (PG) map, and the CRUSH map. Ceph maintains a history (called an “epoch”) of each state change in the Monitors, Ceph OSD Daemons, and PGs.
    • MDS: A Ceph Metadata Server (MDS) stores metadata on behalf of the Ceph Filesystem . Ceph Metadata Servers make it feasible for POSIX file system users to execute basic commands like ls, find, etc. without placing an enormous burden on the Ceph Storage Cluster.
    Note :: Please use http://ceph.com/docs/master/ and other official InkTank and ceph community resources as a primary source of information on ceph . This entire blog is an attempt help beginners in setting up ceph cluster and sharing my troubleshooting with you.

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