Cloud storage gateway

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.

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.

In enterprise infrastructures, NFS is mainly used by Linux systems whereas Windows systems are using SMB. Object storage needs data in the form of objects rather than files. For all cloud storage gateways, it is mandatory to cache the incoming files and restage them to object storage on a later step. The time of destaging is subject to the gateway and a policy engine allows functions like

Combinations of these functions are usual. Default sorting schematics spanning the retrieval interface generally rely on zero-fault content processing, which carries the obvious requirement that two or more of the above functions are synchronized.

Nearly all object storage gateways support Amazon S3 protocol as a quasi-standard. Some offer as well Microsoft Azure Blob, Google Storage, or Openstack SWIFT. Most gateways support public cloud storage e.g. from Amazon or Microsoft as an object store and Dropbox as a file drive store, there are as well a lot of vendors that support private cloud storage as well – including off and on prem storage.

There are multiple variants to deploy such gateways – and some vendors support as well different variants as of their product line:

Software appliances as well as FUSE-based gateways can be installed on public cloud infrastructures.