2 .. _ceph-volume-lvm-api:
6 The backend of ``ceph-volume lvm`` is LVM, it relies heavily on the usage of
7 tags, which is a way for LVM to allow extending its volume metadata. These
8 values can later be queried against devices and it is how they get discovered
11 .. warning:: These APIs are not meant to be public, but are documented so that
12 it is clear what the tool is doing behind the scenes. Do not alter
16 .. _ceph-volume-lvm-tag-api:
20 The process of identifying logical volumes as part of Ceph relies on applying
21 tags on all volumes. It follows a naming convention for the namespace that
24 ceph.<tag name>=<tag value>
26 All tags are prefixed by the ``ceph`` keyword do claim ownership of that
27 namespace and make it easily identifiable. This is how the OSD ID would be used
28 in the context of lvm tags::
33 .. _ceph-volume-lvm-tags:
37 The following describes all the metadata from Ceph OSDs that is stored on an
43 Describes if the device is a an OSD or Journal, with the ability to expand to
44 other types when supported (for example a lockbox)
55 ceph.cluster_fsid=7146B649-AE00-4157-9F5D-1DBFF1D52C26
61 ceph.data_device=/dev/ceph/data-0
67 ceph.journal_device=/dev/ceph/journal-0
71 Example for enabled encryption with ``luks``::
77 ceph.encrypted=dmcrypt
79 For disabled encryption::
87 ceph.osd_fsid=88ab9018-f84b-4d62-90b4-ce7c076728ff
97 Just used on :term:`bluestore` backends.
101 ceph.block=/dev/mapper/vg-block-0
105 Just used on :term:`bluestore` backends.
109 ceph.db=/dev/mapper/vg-db-0
113 Just used on :term:`bluestore` backends.
117 ceph.wal=/dev/mapper/vg-wal-0
122 Only used when encryption is enabled, to store keys in an unencrypted
127 ceph.lockbox_device=/dev/mapper/vg-lockbox-0