cinder/doc/source/devref/drivers.rst

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Drivers

Cinder exposes an API to users to interact with different storage backend solutions. The following are standards across all drivers for Cinder services to properly interact with a driver.

Minimum Features

Minimum features are enforced to avoid having a grid of what features are supported by which drivers and which releases. Cinder Core requires that all drivers implement the following minimum features.

Havana

  • Volume Create/Delete
  • Volume Attach/Detach
  • Snapshot Create/Delete
  • Create Volume from Snapshot
  • Get Volume Stats
  • Copy Image to Volume
  • Copy Volume to Image
  • Clone Volume

Icehouse

  • All of the above plus
  • Extend Volume

Volume Stats

Volume stats are used by the different schedulers for the drivers to provide a report on their current state of the backend. The following should be provided by a driver.

  • driver_version
  • free_capacity_gb
  • reserved_percentage
  • storage_protocol
  • total_capacity_gb
  • vendor_name
  • volume_backend_name

NOTE: If the driver is unable to provide a value for free_capacity_gb or total_capacity_gb, keywords can be provided instead. Please use 'unknown' if the array cannot report the value or 'infinite' if the array has no upper limit.