A cloud storage gateway is a hybrid cloud storage device, implemented in hardware or software, which resides at the customer premises and translates cloud storage APIs such as SOAP or REST to block-based storage protocols such as iSCSI or Fibre Channel or file-based interfaces such as NFS or SMB. According to a 2011 report by Gartner Group, cloud gateways were expected to increase the use of cloud storage by lowering monthly charges and eliminating the concern of data security. Technology Features Modern applications (aka "cloud native applications") use network attached storage by means of REST and SOAP with hypertext transfer protocol on the protocol layer. The related storage is provided from arrays that offer these as object storage. Classic applications use network attached storage by means of Network File System NFS, iSCSI or Server Message Block SMB. To make use of all the advantages of object storage, existing applications need to be rewritten and new applications must be object storage aware, which is not the case by default. This problem is addressed by cloud storage gateways. They offer object storage via classic native storage protocols like Network File System NFS or Server Message Block SMB (and a very few offer iSCSI as well). As a rule of thumb, classic applications with cloud native object storage can now be used with cloud storage gateways. Functionality In enterprise infrastructures NFS is mainly used by Linux systems whereas Windows systems are using SMB. Object storage needs data in form of objects rather than files. For all cloud storage gateways it is mandatory to cache the incoming files and destage them to object storage on a later step. The time of destaging is subject to the gateway and a policy engine allows functions like pinning = bind specific files to the cache and destage them only for mirroring purpose content based destaging = move only files with specific characteristics to object storage e.g. all MP3 files multi-cloud mirroring = mirror all files to two different object stores Least Recently use = fill the local cache to maximum, move all files to object storage and delete files in cache on a LRU algorithm encrypt prior of destage = files are encrypted on the cloud storage gateway and destaged to object storage in an encrypted form compress and/or dedupliation prior of destage = files are deduplicated and/or compressed prior of destaging backup data in a native