Cloud file storage (CFS) is a storage service that is delivered over the Internet, billed on a pay-per-use basis and has an architecture based on common file level protocols such as Server Message Block (SMB), Common Internet File System (CIFS) and Network File System (NFS).
CFS and cloud block storage are the two main types of cloud storage services. (These are akin to the two types of networked storage, NAS or file storage and SAN, or block storage.) Most cloud storage services, including cloud backup services, use a file storage architecture.
Cloud file storage is most appropriate for unstructured data or semi-structured data, such as documents, spreadsheets, presentations and other file-based data. For applications that may have very large files, such as databases, a block storage architecture is more appropriate to maintain satisfactory performance. Only a handful of cloud storage services offer block storage, however, because the bandwidth required to traverse the cloud would not likely be adequate to maintain acceptable database performance without significant latency.