In the cloud as well as on personal PCs, disk I/O speeds remain one of the greatest bottlenecks in computing performance--which is unsurprising, since hard-disk technology has changed little in 20 years. But there's an old trick for bypassing this limitation: In-memory computing, the technology at the core of an open source based NoSQL cloud solution unveiled by Garantia Data. Here are the details, and why they matter for the future of computing in the cloud.

As the term implies, in-memory computing means data is stored in RAM, rather than on hard disks. Since RAM read/write speeds are typically many hundreds of times faster than those of hard drives, in-memory computations provide huge performance increases in a variety of scenarios. In-memory computing has been possible in traditional computing environments for decades--the Linux RAM disk feature is a classic example--and it has been extended to the cloud through work like that of the open source Redis and Memcached projects.

Garantia has leveraged that open source code into two value-added cloud services that became generally available Feb. 14. Called Redis Cloud and Memcached Cloud, the solutions were released in public-beta form in June 2012 and already power more than 1,000 databases, including production environments.

According to Garantia, the two services enhance the basic open source Redis and Memcached packages by delivering features such as automated scaling and failover, making administration easier so developers can focus on production. They also, of course, provide an easy solution for leveraging high-performance data storage in the cloud for organizations seeking a ready-made platform, rather than integrating the open source technologies into the infrastructure themselves.

Another novel component of the Garantia offering is pricing, which is based on what the company describes as a "pay-as-you-go" model. It charges users according to the size of their datasets, measured in Gigabytes-per-hour over the course of a calendar month, rather than by the number of cloud instances they run. That approach will appeal to organizations that want to avoid paying for computing power and memory resources they don't use.

In some senses, the Garantia platforms are far from radically innovative. In-memory computing has existed as a concept for many decades, and the code for making it work in the cloud has been freely available for some time as well. But by packaging that technology along with features that simplify deployment and administration, the company is making an emerging niche within cloud computing a much more practical possibility for many organizations.

In so doing, it's also helping to pioneer new applications for the cloud that bypass the limitations associated with traditional storage techniques based on hard disks. Since the expensive disks spinning in most high-performance servers today, despite storage innovations in recent years including solid-state hybridization, deliver only incrementally better read-write speeds than the 128MB drive that came with the IBM PS/2 I bought in 1993, that's a big deal. And it could become an even more valuable strategy as new RAM technology emerges that supports scenarios such as non-volatile in-memory computing.