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249 lines
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249 lines
9.6 KiB
ReStructuredText
===============
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Ceph Glossary
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===============
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.. glossary::
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:ref:`BlueStore<rados_config_storage_devices_bluestore>`
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OSD BlueStore is a storage back end used by OSD daemons, and
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was designed specifically for use with Ceph. BlueStore was
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introduced in the Ceph Kraken release. In the Ceph Luminous
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release, BlueStore became Ceph's default storage back end,
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supplanting FileStore. Unlike :term:`filestore`, BlueStore
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stores objects directly on Ceph block devices without any file
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system interface. Since Luminous (12.2), BlueStore has been
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Ceph's default and recommended storage back end.
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Ceph
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Ceph is a distributed network storage and file system with
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distributed metadata management and POSIX semantics.
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Ceph Block Device
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A software instrument that orchestrates the storage of
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block-based data in Ceph. Ceph Block Device (also called "RBD",
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or "RADOS block device") splits block-based application data
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into "chunks". RADOS stores these chunks as objects. Ceph Block
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Device orchestrates the storage of those objects across the
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storage cluster. See also :term:`RBD`.
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Ceph Block Storage
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The block storage "product," service or capabilities when used
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in conjunction with ``librbd``, a hypervisor such as QEMU or
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Xen, and a hypervisor abstraction layer such as ``libvirt``.
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Ceph Client
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The collection of Ceph components which can access a Ceph
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Storage Cluster. These include the Ceph Object Gateway, the
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Ceph Block Device, the Ceph File System, and their
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corresponding libraries, kernel modules, and FUSEs.
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Ceph Client Libraries
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The collection of libraries that can be used to interact with
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components of the Ceph System.
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Ceph Cluster Map
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See :term:`Cluster Map`
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Ceph Dashboard
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:ref:`The Ceph Dashboard<mgr-dashboard>` is a built-in
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web-based Ceph management and monitoring application through
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which you can inspect and administer various resources within
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the cluster. It is implemented as a :ref:`ceph-manager-daemon`
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module.
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Ceph File System
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See :term:`CephFS`
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CephFS
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The POSIX filesystem components of Ceph. Refer :ref:`CephFS
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Architecture <arch-cephfs>` and :ref:`ceph-file-system` for
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more details.
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Ceph Interim Release
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A version of Ceph that has not yet been put through quality
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assurance testing. May contain new features.
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Ceph Kernel Modules
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The collection of kernel modules that can be used to interact
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with the Ceph System (for example: ``ceph.ko``, ``rbd.ko``).
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Ceph Manager
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The Ceph manager daemon (ceph-mgr) is a daemon that runs
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alongside monitor daemons to provide monitoring and interfacing
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to external monitoring and management systems. Since the
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Luminous release (12.x), the ceph-mgr daemon is required in
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order for the Ceph cluster to function properly.
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Ceph Manager Dashboard
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Ceph Metadata Server
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Ceph Monitor
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A daemon that maintains a map of the state of the cluster. This
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"cluster state" includes the monitor map, the manager map, the
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OSD map, and the CRUSH map. A minimum of three monitors is
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required in order for the Ceph cluster to be both redundant and
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highly-available. Ceph monitors and the nodes on which they run
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are often referred to as "mon"s. **SEE** :ref:`Monitor Config
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Reference <monitor-config-reference>`.
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Ceph Node
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Ceph Object Gateway
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Ceph Object Storage
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The object storage "product", service or capabilities, which
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consists essentially of a Ceph Storage Cluster and a Ceph Object
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Gateway.
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Ceph Object Store
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:ref:`Ceph OSD<rados_configuration_storage-devices_ceph_osd>`
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Ceph **O**\bject **S**\torage **D**\aemon. The Ceph OSD
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software, which interacts with logical disks (:term:`OSD`).
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Around 2013, there was an attempt by "research and industry"
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(Sage's own words) to insist on using the term "OSD" to mean
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only "Object Storage Device", but the Ceph community has always
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persisted in using the term to mean "Object Storage Daemon" and
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no less an authority than Sage Weil himself confirms in
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November of 2022 that "Daemon is more accurate for how Ceph is
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built" (private correspondence between Zac Dover and Sage Weil,
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07 Nov 2022).
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Ceph OSD Daemon
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Ceph OSD Daemons
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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 Point Release
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Any ad-hoc release that includes only bug or security fixes.
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Ceph Project
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The aggregate term for the people, software, mission and
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infrastructure of Ceph.
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Ceph Release
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Any distinct numbered version of Ceph.
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Ceph Release Candidate
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A major version of Ceph that has undergone initial quality
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assurance 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
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interim releases have been put through quality assurance
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testing successfully.
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Ceph Stack
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A collection of two or more components of Ceph.
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Ceph Storage Cluster
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Ceph System
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Ceph Test Framework
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cephx
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The Ceph authentication protocol. Cephx operates like Kerberos,
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but it has no single point of failure.
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Cloud Platforms
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Cloud Stacks
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Third party cloud provisioning platforms such as OpenStack,
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CloudStack, OpenNebula, and Proxmox VE.
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Cluster Map
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The set of maps comprising the monitor map, OSD map, PG map,
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MDS map and CRUSH map, which together report the state of the
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Ceph cluster. See :ref:`the "Cluster Map" section of the
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Architecture document<architecture_cluster_map>` for details.
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CRUSH
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Controlled Replication Under Scalable Hashing. It is the
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algorithm 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
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pool(s).
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Dashboard
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A built-in web-based Ceph management and monitoring application
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to administer various aspects and objects of the cluster. The
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dashboard is implemented as a Ceph Manager module. See
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:ref:`mgr-dashboard` for more details.
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Dashboard Module
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Dashboard Plugin
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filestore
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A back end for OSD daemons, where a Journal is needed and files
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are written to the filesystem.
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Host
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Any single machine or server in a Ceph System.
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LVM tags
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Extensible metadata for LVM volumes and groups. It is used to
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store Ceph-specific information about devices and its
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relationship with OSDs.
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MDS
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The Ceph metadata software.
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MGR
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The Ceph manager software, which collects all the state from
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the whole cluster in one place.
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MON
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The Ceph monitor software.
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Node
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Object Storage Device
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See :term:`OSD`.
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OSD
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Probably :term:`Ceph Object Storage Daemon<Ceph OSD>`, but not
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necessarily. Sometimes (especially in older correspondence, and
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especially in documentation that is not specifically written
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for Ceph), "OSD" means "**O**\bject **S**\torage **D**\evice",
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which refers to a physical or logical storage unit (for
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example: LUN). The Ceph community has always used the term
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"OSD" to refer to :term:`Ceph OSD Daemon` despite an industry
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push in the mid-2010s to insist that "OSD" should refer to
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"Object Storage Device", so it is important to know which
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meaning is intended.
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OSD fsid
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This is a unique identifier used to further improve the
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uniqueness of an OSD and it is found in the OSD path in a file
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called ``osd_fsid``. This ``fsid`` term is used interchangeably
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with ``uuid``
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OSD id
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The integer that defines an OSD. It is generated by the
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monitors as part of the creation of a new OSD.
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OSD uuid
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Just like the OSD fsid, this is the OSD unique identifier and
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is used interchangeably with ``fsid``
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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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RADOS
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RADOS Cluster
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RADOS Gateway
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RBD
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The block storage component of Ceph.
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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
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(MON+OSD).
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RGW
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The S3/Swift gateway component of Ceph.
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systemd oneshot
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A systemd ``type`` where a command is defined in ``ExecStart``
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which will exit upon completion (it is not intended to
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daemonize)
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Teuthology
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The collection of software that performs scripted tests on Ceph.
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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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