diff --git a/doc/rados/configuration/bluestore-config-ref.rst b/doc/rados/configuration/bluestore-config-ref.rst index 966d0143754..e3287d9b63c 100644 --- a/doc/rados/configuration/bluestore-config-ref.rst +++ b/doc/rados/configuration/bluestore-config-ref.rst @@ -8,18 +8,15 @@ Devices BlueStore manages either one, two, or (in certain cases) three storage devices. -In the simplest case, BlueStore consumes a single (primary) storage -device. The storage device is normally partitioned into two parts: +In the simplest case, BlueStore consumes a single (primary) storage device. +The storage device is normally used as a whole, occupying the full device that +is managed directly by BlueStore. This *primary device* is normally identifed +by a ``block`` symlink in data directory. -#. A small partition is formatted with XFS and contains basic metadata - for the OSD. This *data directory* includes information about the - OSD (its identifier, which cluster it belongs to, and its private - keyring). - -#. The rest of the device is normally a large partition occupying the - rest of the device that is managed directly by BlueStore contains - all of the actual data. This *primary device* is normally identifed - by a ``block`` symlink in data directory. +The data directory is a ``tmpfs`` mount which gets populated (at boot time, or +when ``ceph-volume`` activates it) with all the common OSD files that hold +information about the OSD, like: its identifier, which cluster it belongs to, +and its private keyring. It is also possible to deploy BlueStore across two additional devices: @@ -41,7 +38,7 @@ more, provisioning a DB device makes more sense. The BlueStore journal will always be placed on the fastest device available, so using a DB device will provide the same benefit that the WAL device would while *also* allowing additional metadata to be stored there (if -it will fix). +it will fit). A single-device BlueStore OSD can be provisioned with::