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90 lines
3.4 KiB
ReStructuredText
90 lines
3.4 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 File System` 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 File System clients.
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.. ditaa::
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+---------------+ +------------+ +------------+ +---------------+
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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, the MDS map, and the CRUSH map. These maps are critical
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cluster state required for Ceph daemons to coordinate with each other.
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Monitors are also responsible for managing authentication between
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daemons and clients. At least three monitors are normally required
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for 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 modules to manage and expose Ceph cluster
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information, including a web-based :ref:`mgr-dashboard` and
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`REST API`_. At least two managers are normally required for high
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availability.
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- **Ceph OSDs**: An Object Storage Daemon (:term:`Ceph OSD`,
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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 three Ceph OSDs are normally required for
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redundancy 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 File System` (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 (PG) should
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contain the object, and which OSD should store the placement group. The
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CRUSH algorithm enables the Ceph Storage Cluster to scale, rebalance, and
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recover dynamically.
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.. _REST API: ../../mgr/restful
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.. container:: columns-2
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.. container:: column
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.. raw:: html
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<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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.. container:: column
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.. raw:: html
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<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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