1.5 OpenStack Storage

The storage used in OpenStack can be either ephemeral or persistent. Ephemeral storage is deleted when an instance is terminated, while persistent storage remains intact. Persistent storage in OpenStack is referred to as a volume, regardless of the technology and device it is backed by. Persistent storage can either be used to launch an instance, or it can be connected to an instance as a secondary storage device to retain state. An example of this is a database launched as an ephemeral instance, with a volume connected to it to save the data. When the instance is terminated, the volume retains the data and can be connected to another instance as needed.

The OpenStack Cinder service is responsible for managing the volumes, and it offers a framework for vendors to create drivers. If a storage vendor wants to support OpenStack deployment and allow users to create volumes on the device, the vendor must create a Cinder driver that allows users to use the standard calls to control the storage device.

OpenStack also supports object storage using the Swift service.