Apart from the primary storage, CloudStack has another category of storage known as secondary storage. This storage is associated with a zone, that is, all the hosts in all the clusters in all the pods of a zone have access to the secondary storage of that zone. The secondary storage is used to store templates, ISO images, and snapshots of volumes. The resources stored in the secondary storage are available to all the hosts in the zone.
CloudStack allows NFS server or OpenStack object storage (Swift) to be added as secondary storage. For storage to be added as a secondary storage, it is important that the storage server meets the following requirements: