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1 | =============== |
2 | Intro to Ceph | |
3 | =============== | |
4 | ||
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5 | Whether you want to provide :term:`Ceph Object Storage` and/or |
6 | :term:`Ceph Block Device` services to :term:`Cloud Platforms`, deploy | |
9f95a23c | 7 | a :term:`Ceph File System` or use Ceph for another purpose, all |
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8 | :term:`Ceph Storage Cluster` deployments begin with setting up each |
9 | :term:`Ceph Node`, your network, and the Ceph Storage Cluster. A Ceph | |
10 | Storage Cluster requires at least one Ceph Monitor, Ceph Manager, and | |
11 | Ceph OSD (Object Storage Daemon). The Ceph Metadata Server is also | |
9f95a23c | 12 | required when running Ceph File System clients. |
224ce89b | 13 | |
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14 | .. ditaa:: |
15 | ||
16 | +---------------+ +------------+ +------------+ +---------------+ | |
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17 | | OSDs | | Monitors | | Managers | | MDSs | |
18 | +---------------+ +------------+ +------------+ +---------------+ | |
19 | ||
20 | - **Monitors**: A :term:`Ceph Monitor` (``ceph-mon``) maintains maps | |
21 | of the cluster state, including the monitor map, manager map, the | |
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22 | OSD map, the MDS map, and the CRUSH map. These maps are critical |
23 | cluster state required for Ceph daemons to coordinate with each other. | |
24 | Monitors are also responsible for managing authentication between | |
25 | daemons and clients. At least three monitors are normally required | |
26 | for redundancy and high availability. | |
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27 | |
28 | - **Managers**: A :term:`Ceph Manager` daemon (``ceph-mgr``) is | |
29 | responsible for keeping track of runtime metrics and the current | |
30 | state of the Ceph cluster, including storage utilization, current | |
31 | performance metrics, and system load. The Ceph Manager daemons also | |
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32 | host python-based modules to manage and expose Ceph cluster |
33 | information, including a web-based :ref:`mgr-dashboard` and | |
34 | `REST API`_. At least two managers are normally required for high | |
35 | availability. | |
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36 | |
37 | - **Ceph OSDs**: A :term:`Ceph OSD` (object storage daemon, | |
38 | ``ceph-osd``) stores data, handles data replication, recovery, | |
39 | rebalancing, and provides some monitoring information to Ceph | |
40 | Monitors and Managers by checking other Ceph OSD Daemons for a | |
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41 | heartbeat. At least three Ceph OSDs are normally required for |
42 | redundancy and high availability. | |
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43 | |
44 | - **MDSs**: A :term:`Ceph Metadata Server` (MDS, ``ceph-mds``) stores | |
9f95a23c | 45 | metadata on behalf of the :term:`Ceph File System` (i.e., Ceph Block |
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46 | Devices and Ceph Object Storage do not use MDS). Ceph Metadata |
47 | Servers allow POSIX file system users to execute basic commands (like | |
48 | ``ls``, ``find``, etc.) without placing an enormous burden on the | |
49 | Ceph Storage Cluster. | |
50 | ||
51 | Ceph stores data as objects within logical storage pools. Using the | |
52 | :term:`CRUSH` algorithm, Ceph calculates which placement group should | |
53 | contain the object, and further calculates which Ceph OSD Daemon | |
54 | should store the placement group. The CRUSH algorithm enables the | |
55 | Ceph Storage Cluster to scale, rebalance, and recover dynamically. | |
56 | ||
224ce89b | 57 | .. _REST API: ../../mgr/restful |
7c673cae | 58 | |
20effc67 | 59 | .. container:: columns-2 |
7c673cae | 60 | |
20effc67 | 61 | .. container:: column |
7c673cae | 62 | |
20effc67 | 63 | .. raw:: html |
7c673cae | 64 | |
20effc67 | 65 | <h3>Recommendations</h3> |
7c673cae | 66 | |
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67 | To begin using Ceph in production, you should review our hardware |
68 | recommendations and operating system recommendations. | |
7c673cae | 69 | |
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70 | .. toctree:: |
71 | :maxdepth: 2 | |
7c673cae | 72 | |
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73 | Hardware Recommendations <hardware-recommendations> |
74 | OS Recommendations <os-recommendations> | |
7c673cae | 75 | |
20effc67 | 76 | .. container:: column |
7c673cae | 77 | |
20effc67 | 78 | .. raw:: html |
7c673cae | 79 | |
20effc67 | 80 | <h3>Get Involved</h3> |
7c673cae | 81 | |
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82 | You can avail yourself of help or contribute documentation, source |
83 | code or bugs by getting involved in the Ceph community. | |
7c673cae | 84 | |
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85 | .. toctree:: |
86 | :maxdepth: 2 | |
87 | ||
88 | get-involved | |
89 | documenting-ceph |