2017-08-17 13:25:52 +00:00
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.. _ceph-volume-overview:
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Overview
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--------
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The ``ceph-volume`` tool aims to be a single purpose command line tool to deploy
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logical volumes as OSDs, trying to maintain a similar API to ``ceph-disk`` when
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preparing, activating, and creating OSDs.
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It deviates from ``ceph-disk`` by not interacting or relying on the udev rules
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that come installed for Ceph. These rules allow automatic detection of
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previously setup devices that are in turn fed into ``ceph-disk`` to activate
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them.
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``ceph-volume lvm``
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-------------------
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By making use of :term:`LVM tags`, the :ref:`ceph-volume-lvm` sub-command is
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able to store and later re-discover and query devices associated with OSDs so
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2017-09-01 14:00:35 +00:00
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that they can later activated. This includes support for lvm-based technologies
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like dm-cache as well.
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For ``ceph-volume``, the use of dm-cache is transparent, there is no difference
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for the tool, and it treats dm-cache like a plain logical volume.
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