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9f95a23c | 1 | .. _ceph-file-system: |
91327a77 | 2 | |
7c673cae | 3 | ================= |
9f95a23c | 4 | Ceph File System |
7c673cae FG |
5 | ================= |
6 | ||
9f95a23c TL |
7 | The Ceph File System, or **CephFS**, is a POSIX-compliant file system built on |
8 | top of Ceph's distributed object store, **RADOS**. CephFS endeavors to provide | |
9 | a state-of-the-art, multi-use, highly available, and performant file store for | |
10 | a variety of applications, including traditional use-cases like shared home | |
11 | directories, HPC scratch space, and distributed workflow shared storage. | |
7c673cae | 12 | |
9f95a23c TL |
13 | CephFS achieves these goals through the use of some novel architectural |
14 | choices. Notably, file metadata is stored in a separate RADOS pool from file | |
15 | data and served via a resizable cluster of *Metadata Servers*, or **MDS**, | |
16 | which may scale to support higher throughput metadata workloads. Clients of | |
17 | the file system have direct access to RADOS for reading and writing file data | |
18 | blocks. For this reason, workloads may linearly scale with the size of the | |
19 | underlying RADOS object store; that is, there is no gateway or broker mediating | |
20 | data I/O for clients. | |
7c673cae | 21 | |
9f95a23c TL |
22 | Access to data is coordinated through the cluster of MDS which serve as |
23 | authorities for the state of the distributed metadata cache cooperatively | |
24 | maintained by clients and MDS. Mutations to metadata are aggregated by each MDS | |
25 | into a series of efficient writes to a journal on RADOS; no metadata state is | |
26 | stored locally by the MDS. This model allows for coherent and rapid | |
27 | collaboration between clients within the context of a POSIX file system. | |
7c673cae | 28 | |
9f95a23c | 29 | .. image:: cephfs-architecture.svg |
7c673cae | 30 | |
9f95a23c TL |
31 | CephFS is the subject of numerous academic papers for its novel designs and |
32 | contributions to file system research. It is the oldest storage interface in | |
33 | Ceph and was once the primary use-case for RADOS. Now it is joined by two | |
34 | other storage interfaces to form a modern unified storage system: RBD (Ceph | |
35 | Block Devices) and RGW (Ceph Object Storage Gateway). | |
7c673cae | 36 | |
7c673cae | 37 | |
9f95a23c TL |
38 | Getting Started with CephFS |
39 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
7c673cae | 40 | |
9f95a23c TL |
41 | For most deployments of Ceph, setting up a CephFS file system is as simple as: |
42 | ||
43 | .. code:: bash | |
44 | ||
45 | ceph fs volume create <fs name> | |
46 | ||
47 | The Ceph `Orchestrator`_ will automatically create and configure MDS for | |
48 | your file system if the back-end deployment technology supports it (see | |
49 | `Orchestrator deployment table`_). Otherwise, please `deploy MDS manually | |
50 | as needed`_. | |
51 | ||
52 | Finally, to mount CephFS on your client nodes, see `Mount CephFS: | |
53 | Prerequisites`_ page. Additionally, a command-line shell utility is available | |
54 | for interactive access or scripting via the `cephfs-shell`_. | |
55 | ||
56 | .. _Orchestrator: ../mgr/orchestrator | |
57 | .. _deploy MDS manually as needed: add-remove-mds | |
58 | .. _Orchestrator deployment table: ../mgr/orchestrator/#current-implementation-status | |
59 | .. _Mount CephFS\: Prerequisites: mount-prerequisites | |
60 | .. _cephfs-shell: cephfs-shell | |
7c673cae FG |
61 | |
62 | ||
63 | .. raw:: html | |
64 | ||
9f95a23c | 65 | <!--- |
7c673cae | 66 | |
9f95a23c TL |
67 | Administration |
68 | ^^^^^^^^^^^^^^ | |
7c673cae | 69 | |
9f95a23c TL |
70 | .. raw:: html |
71 | ||
72 | ---> | |
7c673cae FG |
73 | |
74 | .. toctree:: | |
9f95a23c TL |
75 | :maxdepth: 1 |
76 | :hidden: | |
7c673cae | 77 | |
9f95a23c TL |
78 | Create a CephFS file system <createfs> |
79 | Administrative commands <administration> | |
92f5a8d4 | 80 | Provision/Add/Remove MDS(s) <add-remove-mds> |
9f95a23c TL |
81 | MDS failover and standby configuration <standby> |
82 | MDS Cache Size Limits <cache-size-limits> | |
83 | MDS Configuration Settings <mds-config-ref> | |
84 | Manual: ceph-mds <../../man/8/ceph-mds> | |
85 | Export over NFS <nfs> | |
86 | Application best practices <app-best-practices> | |
87 | FS volume and subvolumes <fs-volumes> | |
88 | CephFS Quotas <quota> | |
89 | Health messages <health-messages> | |
90 | Upgrading old file systems <upgrading> | |
91 | ||
7c673cae | 92 | |
9f95a23c | 93 | .. raw:: html |
7c673cae | 94 | |
9f95a23c | 95 | <!--- |
7c673cae | 96 | |
9f95a23c TL |
97 | Mounting CephFS |
98 | ^^^^^^^^^^^^^^^ | |
99 | ||
100 | .. raw:: html | |
101 | ||
102 | ---> | |
7c673cae FG |
103 | |
104 | .. toctree:: | |
9f95a23c TL |
105 | :maxdepth: 1 |
106 | :hidden: | |
107 | ||
108 | Client Configuration Settings <client-config-ref> | |
109 | Client Authentication <client-auth> | |
110 | Mount CephFS: Prerequisites <mount-prerequisites> | |
111 | Mount CephFS using Kernel Driver <mount-using-kernel-driver> | |
112 | Mount CephFS using FUSE <mount-using-fuse> | |
113 | Use the CephFS Shell <cephfs-shell> | |
114 | Supported Features of Kernel Driver <kernel-features> | |
115 | Manual: ceph-fuse <../../man/8/ceph-fuse> | |
116 | Manual: mount.ceph <../../man/8/mount.ceph> | |
117 | Manual: mount.fuse.ceph <../../man/8/mount.fuse.ceph> | |
7c673cae | 118 | |
7c673cae | 119 | |
9f95a23c TL |
120 | .. raw:: html |
121 | ||
122 | <!--- | |
7c673cae | 123 | |
9f95a23c TL |
124 | CephFS Concepts |
125 | ^^^^^^^^^^^^^^^ | |
126 | ||
127 | .. raw:: html | |
7c673cae | 128 | |
9f95a23c | 129 | ---> |
7c673cae FG |
130 | |
131 | .. toctree:: | |
9f95a23c TL |
132 | :maxdepth: 1 |
133 | :hidden: | |
7c673cae | 134 | |
11fdf7f2 | 135 | MDS States <mds-states> |
7c673cae | 136 | POSIX compatibility <posix> |
9f95a23c | 137 | MDS Journaling <mds-journaling> |
7c673cae | 138 | File layouts <file-layouts> |
9f95a23c TL |
139 | Distributed Metadata Cache <mdcache> |
140 | Dynamic Metadata Management in CephFS <dynamic-metadata-management> | |
141 | CephFS IO Path <cephfs-io-path> | |
81eedcae | 142 | LazyIO <lazyio> |
9f95a23c TL |
143 | Directory fragmentation <dirfrags> |
144 | Multiple active MDS daemons <multimds> | |
145 | ||
146 | ||
147 | .. raw:: html | |
148 | ||
149 | <!--- | |
150 | ||
151 | Troubleshooting and Disaster Recovery | |
152 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
153 | ||
154 | .. raw:: html | |
155 | ||
156 | ---> | |
11fdf7f2 TL |
157 | |
158 | .. toctree:: | |
159 | :hidden: | |
160 | ||
9f95a23c TL |
161 | Client eviction <eviction> |
162 | Scrubbing the File System <scrub> | |
163 | Handling full file systems <full> | |
164 | Metadata repair <disaster-recovery-experts> | |
165 | Troubleshooting <troubleshooting> | |
166 | Disaster recovery <disaster-recovery> | |
167 | cephfs-journal-tool <cephfs-journal-tool> | |
168 | ||
7c673cae FG |
169 | |
170 | .. raw:: html | |
171 | ||
9f95a23c TL |
172 | <!--- |
173 | ||
174 | Developer Guides | |
175 | ^^^^^^^^^^^^^^^^ | |
176 | ||
177 | .. raw:: html | |
7c673cae | 178 | |
9f95a23c | 179 | ---> |
7c673cae FG |
180 | |
181 | .. toctree:: | |
9f95a23c TL |
182 | :maxdepth: 1 |
183 | :hidden: | |
7c673cae | 184 | |
9f95a23c | 185 | Journaler Configuration <journaler> |
7c673cae | 186 | Client's Capabilities <capabilities> |
9f95a23c | 187 | libcephfs for Java <../../api/libcephfs-java/> |
7c673cae FG |
188 | Mantle <mantle> |
189 | ||
9f95a23c TL |
190 | |
191 | .. raw:: html | |
192 | ||
193 | <!--- | |
194 | ||
195 | Additional Details | |
196 | ^^^^^^^^^^^^^^^^^^ | |
197 | ||
198 | .. raw:: html | |
199 | ||
200 | ---> | |
201 | ||
202 | .. toctree:: | |
203 | :maxdepth: 1 | |
204 | :hidden: | |
205 | ||
206 | Experimental Features <experimental-features> |