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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
commit | 19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch) | |
tree | 42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /doc/dev/ceph-volume/lvm.rst | |
parent | Initial commit. (diff) | |
download | ceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.tar.xz ceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.zip |
Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/dev/ceph-volume/lvm.rst')
-rw-r--r-- | doc/dev/ceph-volume/lvm.rst | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/doc/dev/ceph-volume/lvm.rst b/doc/dev/ceph-volume/lvm.rst new file mode 100644 index 000000000..f2df6d850 --- /dev/null +++ b/doc/dev/ceph-volume/lvm.rst @@ -0,0 +1,179 @@ + +.. _ceph-volume-lvm-api: + +LVM +=== +The backend of ``ceph-volume lvm`` is LVM, it relies heavily on the usage of +tags, which is a way for LVM to allow extending its volume metadata. These +values can later be queried against devices and it is how they get discovered +later. + +.. warning:: These APIs are not meant to be public, but are documented so that + it is clear what the tool is doing behind the scenes. Do not alter + any of these values. + + +.. _ceph-volume-lvm-tag-api: + +Tag API +------- +The process of identifying logical volumes as part of Ceph relies on applying +tags on all volumes. It follows a naming convention for the namespace that +looks like:: + + ceph.<tag name>=<tag value> + +All tags are prefixed by the ``ceph`` keyword to claim ownership of that +namespace and make it easily identifiable. This is how the OSD ID would be used +in the context of lvm tags:: + + ceph.osd_id=0 + + +.. _ceph-volume-lvm-tags: + +Metadata +-------- +The following describes all the metadata from Ceph OSDs that is stored on an +LVM volume: + + +``type`` +-------- +Describes if the device is an OSD or Journal, with the ability to expand to +other types when supported (for example a lockbox) + +Example:: + + ceph.type=osd + + +``cluster_fsid`` +---------------- +Example:: + + ceph.cluster_fsid=7146B649-AE00-4157-9F5D-1DBFF1D52C26 + + +``data_device`` +--------------- +Example:: + + ceph.data_device=/dev/ceph/data-0 + + +``data_uuid`` +------------- +Example:: + + ceph.data_uuid=B76418EB-0024-401C-8955-AE6919D45CC3 + + +``journal_device`` +------------------ +Example:: + + ceph.journal_device=/dev/ceph/journal-0 + + +``journal_uuid`` +---------------- +Example:: + + ceph.journal_uuid=2070E121-C544-4F40-9571-0B7F35C6CB2B + + +``encrypted`` +------------- +Example for enabled encryption with ``luks``:: + + ceph.encrypted=1 + +When encryption is not supported or simply disabled:: + + ceph.encrypted=0 + + +``osd_fsid`` +------------ +Example:: + + ceph.osd_fsid=88ab9018-f84b-4d62-90b4-ce7c076728ff + + +``osd_id`` +---------- +Example:: + + ceph.osd_id=1 + + +``block_device`` +---------------- +Just used on :term:`bluestore` backends. Captures the path to the logical +volume path. + +Example:: + + ceph.block_device=/dev/mapper/vg-block-0 + + +``block_uuid`` +-------------- +Just used on :term:`bluestore` backends. Captures either the logical volume UUID or +the partition UUID. + +Example:: + + ceph.block_uuid=E5F041BB-AAD4-48A8-B3BF-31F7AFD7D73E + + +``db_device`` +------------- +Just used on :term:`bluestore` backends. Captures the path to the logical +volume path. + +Example:: + + ceph.db_device=/dev/mapper/vg-db-0 + + +``db_uuid`` +----------- +Just used on :term:`bluestore` backends. Captures either the logical volume UUID or +the partition UUID. + +Example:: + + ceph.db_uuid=F9D02CF1-31AB-4910-90A3-6A6302375525 + + +``wal_device`` +-------------- +Just used on :term:`bluestore` backends. Captures the path to the logical +volume path. + +Example:: + + ceph.wal_device=/dev/mapper/vg-wal-0 + + +``wal_uuid`` +------------ +Just used on :term:`bluestore` backends. Captures either the logical volume UUID or +the partition UUID. + +Example:: + + ceph.wal_uuid=A58D1C68-0D6E-4CB3-8E99-B261AD47CC39 + + +``vdo`` +------- +A VDO-enabled device is detected when device is getting prepared, and then +stored for later checks when activating. This affects mount options by +appending the ``discard`` mount flag, regardless of mount flags being used. + +Example for an enabled VDO device:: + + ceph.vdo=1 |