OpenStack Block Storage provides the software to create and centrally manage a service that provisions storage in the form of block devices known as Cinder volumes. Under the most common scenario, the Cinder volumes provide persistent storage to guest virtual machines (known as instances) that are managed by OpenStack Compute software. Cinder can also be used independently of other OpenStack services.
Cinder permits organizations that deploy it to make available a catalog of block-based storage devices with differing characteristics. For instance, one potential storage volume type might be a high-performance option for database storage. Cinder also features basic storage capabilities such as snapshot management and volume clones, which are often enhanced through vendor-specific drivers.
The physical storage media, whether disks or solid-state drives, can be located within or directly attached to the Cinder server nodes, or they can be located in external storage systems from third-party vendors. Third-party storage vendors use Cinder's plug-in architecture to do the necessary integration work. The back-end path from the external storage systems to the compute nodes where the hypervisors are located can be iSCSI, Network File System (NFS) or Fibre Channel.
Cinder was originally a component of the Nova project, which is the code name for the OpenStack Compute service. It was known as "nova-volume" until the project broke off into the independent Cinder project. The first release of Cinder emerged in the fall of 2012.