Cloud-integrated storage (CIS) is a conventional storage-area network (SAN), network-attached storage (NAS) or unified storage system that tiers and/or caches data to cloud-based storage and treats the cloud storage as if it were part of the primary storage system.
The conventional storage system is typically housed on-premises and manages both the local and cloud-based storage; cloud data appears as if it's local. In a common scenario, the CIS system automatically tiers or caches the most active data to local storage for speedier access and uses the cloud-based storage for less active data. The user is able to employ features of the primary storage system, such as snapshots, thin provisioning and data reduction with the cloud-based data.
Additional CIS variations include:
- On-premises storage used in conjunction with an integrated connection to cloud storage
- Systems that treat the cloud-based storage as the primary storage target and use a local appliance to hold only cached data
- Systems that use software to create a geographically distributed cluster that combines the capacity of the local storage and the cloud storage.
Proponents of CIS systems say they afford users the flexibility and economic advantages of cloud storage while also giving them the familiarity, functionality, control and performance of traditional storage systems. Some on-site hardware- or software-based cloud storage gateway products that primarily served as on-ramps to cloud storage in the past are picking up additional capabilities to turn them into more comprehensive CIS systems.