From 3521c2bdad05fac6d310fa5a55d70c2b1fdc0899 Mon Sep 17 00:00:00 2001 From: Zac Dover Date: Sun, 30 Oct 2022 15:27:24 +1000 Subject: [PATCH] doc/ceph-volume: refine Filestore docs Add Cole Mitchell's improvements to the filestore section. Signed-off-by: Zac Dover (cherry picked from commit d5717fe2648451d48f39f30163c6e4af7eaa7a09) --- doc/ceph-volume/lvm/prepare.rst | 36 +++++++++++++++++---------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/doc/ceph-volume/lvm/prepare.rst b/doc/ceph-volume/lvm/prepare.rst index e5190a288c906..e77906f4bb8d1 100644 --- a/doc/ceph-volume/lvm/prepare.rst +++ b/doc/ceph-volume/lvm/prepare.rst @@ -10,8 +10,8 @@ logical volume. ``prepare`` adds metadata to logical volumes but does not alter them in any other way. -.. note:: This is part of a two-step process to deploy an OSD. If you prefer a - single-call method of deploying an OSD, see :ref:`ceph-volume-lvm-create`. +.. note:: This is part of a two-step process to deploy an OSD. If you prefer + to deploy an OSD by using only one command, see :ref:`ceph-volume-lvm-create`. ``prepare`` uses :term:`LVM tags` to assign several pieces of metadata to a logical volume. Volumes tagged in this way are easier to identify and easier to @@ -78,7 +78,7 @@ the files needed for the OSD. These files are created by ``ceph-osd --mkfs`` and are ephemeral. A symlink is created for the ``block`` device, and is optional for ``block.db`` -and ``block.wal``. For a cluster with a default name and an OSD id of 0, the +and ``block.wal``. For a cluster with a default name and an OSD ID of 0, the directory looks like this:: # ls -l /var/lib/ceph/osd/ceph-0 @@ -105,18 +105,20 @@ a volume group and a logical volume using the following conventions: ``filestore`` ------------- -``filestore`` is the OSD backend that prepares logical volumes for a +``Filestore`` is the OSD backend that prepares logical volumes for a :term:`filestore`-backed object-store OSD. -``filestore`` can use a logical volume for OSD data, and it can use a physical -device, a partition, or a logical volume for the journal. If a physical device -is used to create a filestore backend, a logical volume will be created on that -physical device. A volume group will either be created or reused if its name -begins with ``ceph``. No special preparation is needed for these volumes other -than making sure to adhere to the minimum size requirements for data and for -the journal. -Use this command to create a basic filestore OSD: +``Filestore`` uses a logical volume to store OSD data and it uses +physical devices, partitions, or logical volumes to store the journal. If a +physical device is used to create a filestore backend, a logical volume will be +created on that physical device. If the provided volume group's name begins +with `ceph`, it will be created if it does not yet exist and it will be +clobbered and reused if it already exists. No special preparation is needed for +these volumes, but be sure to meet the minimum size requirements for OSD data and +for the journal. + +Use the following command to create a basic filestore OSD: .. prompt:: bash # @@ -134,7 +136,7 @@ Use this command to enable :ref:`encryption `, and n ceph-volume lvm prepare --filestore --dmcrypt --data --journal -Both the journal and the data block device can take three forms: +The data block device and the journal can each take one of three forms: * a physical block device * a partition on a physical block device @@ -142,8 +144,8 @@ Both the journal and the data block device can take three forms: If you use a logical volume to deploy filestore, the value that you pass in the command *must* be of the format ``volume_group/logical_volume_name``. Since logical -volume names are not enforced for uniqueness, using this format is meant to -guard against accidentally choosing the wrong volume (and clobbering its data). +volume names are not enforced for uniqueness, using this format is an important +safeguard against accidentally choosing the wrong volume (and clobbering its data). If you use a partition to deploy filestore, the partition *must* contain a ``PARTUUID`` that can be discovered by ``blkid``. This ensures that the @@ -171,13 +173,13 @@ The OSD data directory is created using the following convention:: /var/lib/ceph/osd/- -To link the journal volume to the mounted data volume, run this command: +To link the journal volume to the mounted data volume, use this command: .. prompt:: bash # ln -s /path/to/journal /var/lib/ceph/osd/-/journal -To fetch the monmap by using the bootstrap key from the OSD, run this command: +To fetch the monmap by using the bootstrap key from the OSD, use this command: .. prompt:: bash # -- 2.39.5