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+===============
+ Intro to Ceph
+===============
+
+Whether you want to provide :term:`Ceph Object Storage` and/or
+:term:`Ceph Block Device` services to :term:`Cloud Platforms`, deploy
+a :term:`Ceph Filesystem` or use Ceph for another purpose, all
+:term:`Ceph Storage Cluster` deployments begin with setting up each
+:term:`Ceph Node`, your network, and the Ceph Storage Cluster. A Ceph
+Storage Cluster requires at least one Ceph Monitor, Ceph Manager, and
+Ceph OSD (Object Storage Daemon). The Ceph Metadata Server is also
+required when running Ceph Filesystem clients.
+
+.. ditaa:: +---------------+ +------------+ +------------+ +---------------+
+ | OSDs | | Monitors | | Managers | | MDSs |
+ +---------------+ +------------+ +------------+ +---------------+
+
+- **Monitors**: A :term:`Ceph Monitor` (``ceph-mon``) maintains maps
+ of the cluster state, including the monitor map, manager map, the
+ OSD map, and the CRUSH map. These maps are critical cluster state
+ required for Ceph daemons to coordinate with each other. Monitors
+ are also responsible for managing authentication between daemons and
+ clients. At least three monitors are normally required for
+ redundancy and high availability.
+
+- **Managers**: A :term:`Ceph Manager` daemon (``ceph-mgr``) is
+ responsible for keeping track of runtime metrics and the current
+ state of the Ceph cluster, including storage utilization, current
+ performance metrics, and system load. The Ceph Manager daemons also
+ host python-based plugins to manage and expose Ceph cluster
+ information, including a web-based `dashboard`_ and `REST API`_. At
+ least two managers are normally required for high availability.
+
+- **Ceph OSDs**: A :term:`Ceph OSD` (object storage daemon,
+ ``ceph-osd``) stores data, handles data replication, recovery,
+ rebalancing, and provides some monitoring information to Ceph
+ Monitors and Managers by checking other Ceph OSD Daemons for a
+ heartbeat. At least 3 Ceph OSDs are normally required for redundancy
+ and high availability.
+
+- **MDSs**: A :term:`Ceph Metadata Server` (MDS, ``ceph-mds``) stores
+ metadata on behalf of the :term:`Ceph Filesystem` (i.e., Ceph Block
+ Devices and Ceph Object Storage do not use MDS). Ceph Metadata
+ Servers allow POSIX file system users to execute basic commands (like
+ ``ls``, ``find``, etc.) without placing an enormous burden on the
+ Ceph Storage Cluster.
+
+Ceph stores data as objects within logical storage pools. Using the
+:term:`CRUSH` algorithm, Ceph calculates which placement group should
+contain the object, and further calculates which Ceph OSD Daemon
+should store the placement group. The CRUSH algorithm enables the
+Ceph Storage Cluster to scale, rebalance, and recover dynamically.
+
+.. _dashboard: ../../mgr/dashboard
+.. _REST API: ../../mgr/restful
+
+.. raw:: html
+
+ <style type="text/css">div.body h3{margin:5px 0px 0px 0px;}</style>
+ <table cellpadding="10"><colgroup><col width="50%"><col width="50%"></colgroup><tbody valign="top"><tr><td><h3>Recommendations</h3>
+
+To begin using Ceph in production, you should review our hardware
+recommendations and operating system recommendations.
+
+.. toctree::
+ :maxdepth: 2
+
+ Hardware Recommendations <hardware-recommendations>
+ OS Recommendations <os-recommendations>
+
+
+.. raw:: html
+
+ </td><td><h3>Get Involved</h3>
+
+ You can avail yourself of help or contribute documentation, source
+ code or bugs by getting involved in the Ceph community.
+
+.. toctree::
+ :maxdepth: 2
+
+ get-involved
+ documenting-ceph
+
+.. raw:: html
+
+ </td></tr></tbody></table>