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This commit improves the grammar in doc/cephfs/snapshots.rst. The PR associated with this commit follows from https://github.com/ceph/ceph/pull/61240, the PR raised by Neeraj Pratap Singh to introduce information about snapshots into the CephFS documentation. See also https://tracker.ceph.com/issues/68974. Signed-off-by: Zac Dover <zac.dover@proton.me>
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================
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CephFS Snapshots
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================
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CephFS snapshots create an immutable view of the file system at the point in
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time they are taken. CephFS snapshots are managed in a special hidden
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subdirectory named ``.snap``. Snapshots are created using ``mkdir`` inside the
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``.snap`` directory.
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Snapshots can be exposed with different names by changing the following client
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configurations:
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- ``snapdirname`` which is a mount option for kernel clients
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- ``client_snapdir`` which is a mount option for ceph-fuse.
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Snapshot Creation
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==================
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The CephFS snapshot feature is enabled by default on new file systems. To
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enable the CephFS snapshot feature on existing file systems, use the command
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below.
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.. code-block:: bash
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$ ceph fs set <fs_name> allow_new_snaps true
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When snapshots are enabled, all directories in CephFS will have a special
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``.snap`` directory. (You may configure a different name with the client's
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``snapdir`` setting if you wish.) To create a CephFS snapshot, create a
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subdirectory under ``.snap`` with a name of your choice. For example, to
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create a snapshot on directory ``/file1/``, run the command ``mkdir
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/file1/.snap/snapshot-name``:
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.. code-block:: bash
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$ touch file1
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$ cd .snap
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$ mkdir my_snapshot
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Using Snapshots to Recover Data
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===============================
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Snapshots can also be used to recover deleted files:
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- ``create a file1 and create snapshot snap1``
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.. code-block:: bash
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$ touch /mnt/cephfs/file1
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$ cd .snap
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$ mkdir snap1
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- ``create a file2 and create snapshot snap2``
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.. code-block:: bash
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$ touch /mnt/cephfs/file2
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$ cd .snap
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$ mkdir snap2
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- ``delete file1 and create a new snapshot snap3``
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.. code-block:: bash
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$ rm /mnt/cephfs/file1
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$ cd .snap
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$ mkdir snap3
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- ``recover file1 using snapshot snap2 using cp command``
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.. code-block:: bash
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$ cd .snap
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$ cd snap2
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$ cp file1 /mnt/cephfs/
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Snapshot Deletion
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==================
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Snapshots are deleted by running ``rmdir`` on the ``.snap`` directory that they
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are rooted in. (Attempts to delete a directory that roots the snapshots will
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fail. You must delete the snapshots first.)
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.. code-block:: bash
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$ cd .snap
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$ rmdir my_snapshot
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