Ceph is growing rapidly. As firms deploy Ceph, the technical terms such as
“RADOS”, “RBD,” “RGW” and so forth require corresponding marketing terms
that explain what each component does. The terms in this glossary are
intended to complement the existing technical terminology.
Sometimes more than one term applies to a definition. Generally, the first
term reflects a term consistent with Ceph’s marketing, and secondary terms
reflect either technical terms or legacy ways of referring to Ceph systems.
- Ceph Project
- The aggregate term for the people, software, mission and infrastructure
- The Ceph authentication protocol. Cephx operates like Kerberos, but it
has no single point of failure.
- All Ceph software, which includes any piece of code hosted at
- Ceph System
- A collection of two or more components of Ceph.
- Ceph Node
- Any single machine or server in a Ceph System.
- Ceph Storage Cluster
Ceph Object Store
Reliable Autonomic Distributed Object Store
- The core set of storage software which stores the user’s data (MON+OSD).
- Ceph Cluster Map
- The set of maps comprising the monitor map, OSD map, PG map, MDS map and
CRUSH map. See Cluster Map for details.
- Ceph Object Storage
- The object storage “product”, service or capabilities, which consists
essentially of a Ceph Storage Cluster and a Ceph Object Gateway.
- Ceph Object Gateway
- The S3/Swift gateway component of Ceph.
- Ceph Block Device
- The block storage component of Ceph.
- Ceph Block Storage
- The block storage “product,” service or capabilities when used in
conjunction with librbd, a hypervisor such as QEMU or Xen, and a
hypervisor abstraction layer such as libvirt.
- Ceph Filesystem
- The POSIX filesystem components of Ceph.
- Cloud Platforms
- Third party cloud provisioning platforms such as OpenStack, CloudStack,
OpenNebula, ProxMox, etc.
- Object Storage Device
- A physical or logical storage unit (e.g., LUN).
Sometimes, Ceph users use the
term “OSD” to refer to Ceph OSD Daemon, though the
proper term is “Ceph OSD”.
- Ceph OSD Daemon
- The Ceph OSD software, which interacts with a logical
disk (OSD). Sometimes, Ceph users use the
term “OSD” to refer to “Ceph OSD Daemon”, though the
proper term is “Ceph OSD”.
- Ceph Monitor
- The Ceph monitor software.
- Ceph Metadata Server
- The Ceph metadata software.
- Ceph Clients
- The collection of Ceph components which can access a Ceph Storage
Cluster. These include the Ceph Object Gateway, the Ceph Block Device,
the Ceph Filesystem, and their corresponding libraries, kernel modules,
- Ceph Kernel Modules
- The collection of kernel modules which can be used to interact with the
Ceph System (e.g,. ceph.ko, rbd.ko).
- Ceph Client Libraries
- The collection of libraries that can be used to interact with components
of the Ceph System.
- Ceph Release
- Any distinct numbered version of Ceph.
- Ceph Point Release
- Any ad-hoc release that includes only bug or security fixes.
- Ceph Interim Release
- Versions of Ceph that have not yet been put through quality assurance
testing, but may contain new features.
- Ceph Release Candidate
- A major version of Ceph that has undergone initial quality assurance
testing and is ready for beta testers.
- Ceph Stable Release
- A major version of Ceph where all features from the preceding interim
releases have been put through quality assurance testing successfully.
- Ceph Test Framework
- The collection of software that performs scripted tests on Ceph.
- Controlled Replication Under Scalable Hashing. It is the algorithm
Ceph uses to compute object storage locations.
- A set of CRUSH data placement rules that applies to a particular pool(s).
- Pools are logical partitions for storing objects.