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aea9fa01ae
Since kraken, Ceph enforces a 1:1 correspondence between CRUSH ruleset and CRUSH rule, so effectively ruleset and rule are the same thing, although the term "ruleset" still survives - notably in the CRUSH rule itself, where it effectively denotes the number of the rule. This commit updates the documentation to more faithfully reflect the current state of the code. Fixes: http://tracker.ceph.com/issues/20559 Signed-off-by: Nathan Cutler <ncutler@suse.com>
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5.3 KiB
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188 lines
5.3 KiB
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===============
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Ceph Glossary
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===============
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Ceph is growing rapidly. As firms deploy Ceph, the technical terms such as
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"RADOS", "RBD," "RGW" and so forth require corresponding marketing terms
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that explain what each component does. The terms in this glossary are
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intended to complement the existing technical terminology.
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Sometimes more than one term applies to a definition. Generally, the first
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term reflects a term consistent with Ceph's marketing, and secondary terms
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reflect either technical terms or legacy ways of referring to Ceph systems.
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.. glossary::
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Ceph Project
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The aggregate term for the people, software, mission and infrastructure
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of Ceph.
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cephx
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The Ceph authentication protocol. Cephx operates like Kerberos, but it
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has no single point of failure.
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Ceph
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Ceph Platform
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All Ceph software, which includes any piece of code hosted at
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`https://github.com/ceph`_.
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Ceph System
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Ceph Stack
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A collection of two or more components of Ceph.
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Ceph Node
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Node
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Host
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Any single machine or server in a Ceph System.
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Ceph Storage Cluster
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Ceph Object Store
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RADOS
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RADOS Cluster
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Reliable Autonomic Distributed Object Store
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The core set of storage software which stores the user's data (MON+OSD).
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Ceph Cluster Map
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cluster map
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The set of maps comprising the monitor map, OSD map, PG map, MDS map and
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CRUSH map. See `Cluster Map`_ for details.
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Ceph Object Storage
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The object storage "product", service or capabilities, which consists
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essentially of a Ceph Storage Cluster and a Ceph Object Gateway.
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Ceph Object Gateway
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RADOS Gateway
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RGW
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The S3/Swift gateway component of Ceph.
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Ceph Block Device
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RBD
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The block storage component of Ceph.
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Ceph Block Storage
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The block storage "product," service or capabilities when used in
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conjunction with ``librbd``, a hypervisor such as QEMU or Xen, and a
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hypervisor abstraction layer such as ``libvirt``.
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Ceph Filesystem
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CephFS
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Ceph FS
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The POSIX filesystem components of Ceph.
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Cloud Platforms
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Cloud Stacks
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Third party cloud provisioning platforms such as OpenStack, CloudStack,
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OpenNebula, ProxMox, etc.
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Object Storage Device
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OSD
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A physical or logical storage unit (*e.g.*, LUN).
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Sometimes, Ceph users use the
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term "OSD" to refer to :term:`Ceph OSD Daemon`, though the
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proper term is "Ceph OSD".
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Ceph OSD Daemon
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Ceph OSD Daemons
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Ceph OSD
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The Ceph OSD software, which interacts with a logical
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disk (:term:`OSD`). Sometimes, Ceph users use the
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term "OSD" to refer to "Ceph OSD Daemon", though the
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proper term is "Ceph OSD".
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OSD id
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The integer that defines an OSD. It is generated by the monitors as part
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of the creation of a new OSD.
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OSD fsid
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This is a unique identifier used to further improve the uniqueness of an
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OSD and it is found in the OSD path in a file called ``osd_fsid``. This
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``fsid`` term is used interchangeably with ``uuid``
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OSD uuid
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Just like the OSD fsid, this is the OSD unique identifer and is used
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interchangeably with ``fsid``
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bluestore
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OSD BlueStore is a new back end for OSD daemons (kraken and newer
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versions). Unlike :term:`filestore` it stores objects directly on the
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Ceph block devices without any file system interface.
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filestore
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A back end for OSD daemons, where a Journal is needed and files are
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written to the filesystem.
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Ceph Monitor
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MON
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The Ceph monitor software.
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Ceph Manager
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MGR
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The Ceph manager software, which collects all the state from the whole
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cluster in one place.
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Ceph Metadata Server
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MDS
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The Ceph metadata software.
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Ceph Clients
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Ceph Client
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The collection of Ceph components which can access a Ceph Storage
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Cluster. These include the Ceph Object Gateway, the Ceph Block Device,
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the Ceph Filesystem, and their corresponding libraries, kernel modules,
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and FUSEs.
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Ceph Kernel Modules
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The collection of kernel modules which can be used to interact with the
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Ceph System (e.g., ``ceph.ko``, ``rbd.ko``).
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Ceph Client Libraries
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The collection of libraries that can be used to interact with components
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of the Ceph System.
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Ceph Release
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Any distinct numbered version of Ceph.
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Ceph Point Release
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Any ad-hoc release that includes only bug or security fixes.
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Ceph Interim Release
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Versions of Ceph that have not yet been put through quality assurance
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testing, but may contain new features.
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Ceph Release Candidate
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A major version of Ceph that has undergone initial quality assurance
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testing and is ready for beta testers.
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Ceph Stable Release
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A major version of Ceph where all features from the preceding interim
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releases have been put through quality assurance testing successfully.
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Ceph Test Framework
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Teuthology
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The collection of software that performs scripted tests on Ceph.
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CRUSH
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Controlled Replication Under Scalable Hashing. It is the algorithm
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Ceph uses to compute object storage locations.
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CRUSH rule
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The CRUSH data placement rule that applies to a particular pool(s).
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Pool
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Pools
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Pools are logical partitions for storing objects.
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systemd oneshot
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A systemd ``type`` where a command is defined in ``ExecStart`` which will
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exit upon completion (it is not intended to daemonize)
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LVM tags
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Extensible metadata for LVM volumes and groups. It is used to store
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Ceph-specific information about devices and its relationship with
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OSDs.
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.. _https://github.com/ceph: https://github.com/ceph
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.. _Cluster Map: ../architecture#cluster-map
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