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