Amazon's gateway to mainstream public cloud

Amazon has become the first major cloud operator to launch its own storage gateway, underlining the potential demand for public cloud storage.

Like other storage gateways, the device provides a simple way to link existing, on-premise applications to cloud storage. Unlike other gateways, it works with only one cloud: Amazon Simple Storage Service (Amazon S3). It is also limited in functionality. However, it is relatively cheap, and it will be developed.

The storage gateway will currently appeal to small and mid-sized businesses that want to single-source their public cloud technologies. Simply by carrying the Amazon name it will raise awareness of the existence of gateways and their ability to provide both a low-cost mechanism for disaster recovery and a free alternative backup to conventional on-premise storage. Other cloud storage providers are likely to follow Amazon's lead.

Gateways transform storage clouds

In their raw state, public storage clouds are not enterprise-friendly. They raise security issues, use non-standard storage protocols, and their performance is significantly affected by network latencies. These problems are solved or significantly reduced by using gateways that are installed on customers' premises.

Gateways translate between storage protocols, and store local, cache copies of frequently-used data to eliminate network latencies. They also encrypt data before it is sent to a cloud, and perform other tasks, such as de-duplicating data (to reduce bandwidth consumption) and creating data snapshots (which are sent to the clouds for backup and disaster recovery).

Cloud storage gateways have been pioneered almost entirely by a clutch of start-ups, including Nasuni, Panzura, Ctera, StorSimple, and TwinStrata (see The Public Clouds Take Shape for Storage). Those companies' gateways allow customers to choose from a handful of back-end storage clouds, of which the two most popular are Amazon S3 and Microsoft's Windows Azure Storage Services. Other large operators are also moving into cloud storage: Google, HP, and IBM have all announced or launched raw data storage services.

Taking it up to gateway makers

Amazon's gateway is a VMware-based software virtual appliance, and its limited functionality and capacity compared to other gateways will restrict its appeal. Among the features it is missing are data de-duplication, encryption using keys held only by the customer, and the data caching needed to allow the gateway to handle live working data and not just backup copies of data for disaster recovery.

Amazon is already developing a caching function for its gateway, and it could easily do the same for the other missing features. Even if it does plug all the gaps in functionality, however, its gateway would still have two major disadvantages. The first is that the device is delivered only as a virtual appliance, unlike its rivals. Although there are advantages to this approach, many customers want a physical gateway, ready-configured for high availability. It is hard to imagine Amazon becoming a hardware supplier in order to overcome this issue. Even if it did, the gateway would still have the second major disadvantage: supporting only Amazon S3. This is a problem because the other gateways offer a choice of back-end clouds, and so provide customers with a way to avoid cloud lock-in.

The existing gateway providers are already creating business for Amazon S3. If Amazon competes too strongly with them, they might retaliate by removing S3 from the list of back-end clouds that their gateways support. Although S3 is currently very popular, gateway makers could take this step without risking a huge loss of business because there are strong alternatives in what is a commoditizing market for cloud services.

Multiple motives 

So why has Amazon made this move? Ovum suspects that there were multiple motives. It will give the company first-hand experience of the gateway market and the way that customers use the devices.

This will give it a better understanding of how to promote and develop S3 as a storage service, and how to help third-party gateway providers make the best use of the service. It will also bring in revenue directly through the monthly gateway subscription fee, as well as generate business for S3 as customers use the gateway to upload data into the Amazon cloud. Once that data is in S3, Amazon will encourage customers to connect it up to rented Amazon Elastic Compute Cloud (EC2) virtual servers. For Amazon, the more customer entry points into its cloud, the better.

Tim Stammers is a member of the IT Infrastructure team at Ovum.