June 7, 2011

Startup Cooks Up Software Sauce for SSDs

Nicole Hemsoth

A small startup emerged from stealth mode today to announce software that improves the read and write performance of SSDs. Although their product won’t appear until later in the year, they claim their solution packs an order of magnitude price-performance improvement for solid-state drives (SSDs) and, for that matter, anything with a block storage interface.

According to Massachusetts-based VeloBit, which just scored an undisclosed round of Series A funding, SSDs can be simpler to deploy without the need for application or existing storage system manipulation.

CEO and founder, Duncan McCallum is no stranger to technology startups. Before he embarked on the VeloBit venture, he served as CEO for Cilk Arts, a multicore software vendor that was swept up by Intel. Before that the MIT and Harvard Business School alum spent a decade in venture capital circles working as a partner at Bessemer Venture Partners and Flagship Ventures.

McCallum’s co-founder, Qing Yang serves as CTO, bringing his 20 years of computer architecture research to bear. His focus has been on securing patents in the areas of memory and storage architectures, disk I/O systems, as well as parallel and distributed computing

McCallum claims that customers who invest in SSD technology are often already plagued with storage problems, but using SSDs still comes bundled with performance limitations. He says that customers who have made the SSD leap are left with two issues. First they have a write problem since it’s much slower to write to an SSD than to read from it. He acknowledges that this can be solved by companies with workarounds like EMC and Fusion-io but these are expensive fixes for a problem that can be handled off the SSD. According to McCallum, the software-only approach VeloBit created means there is no need for heavy investments beyond the SSDs themselves.

In addition to the write issue, McCallum claims that the complexity of using SSDs alone creates a number of challenges since customers are faced with big investments to simplify data management and protection. He says ‘if you look at a dedicated SSD system like Fusion-io, for instances, you’re changing primary storage and you’re left with data on a system that is not part of your legacy infrastructure…what you’re left with is a data island.”

There are other ways to approach these problems, including buying an SSD from one of several system vendors and put it in as a tier, but McCallum says that when you do this, you’re left with data tiering problems. This requires a thorough inventory of data to determine what data is hot and thus suitable to reside on the expensive SSD, with the rest relegated to the cheaper disk storage. Since your “hot” data can change with the times, this means you’re left moving data around accordingly, which adds complexity and cost.

To solve these problems VeloBit’s software-only approach weaves together caching and data compression. He told us that the compression is happening at line speed, creating a large cache that drives performance. The other ingredient in their software sauce is that they are able to use the SSD to expand the cache, and can thus organize the data in such a way that they can make use of the device as a read cache. McCallum says that when you put these capabilities together, it is possible to use less SSDs and on top of that, to use cheaper ones.

The best description he could give was the pyramid example. Imagine that at the top the server running the application needs to be faster. At that bottom of that pyramid is your primary storage—anything with a block interface—and in between those two is VeloBit’s solution. But here’s the catch. Sitting off to the side of that pyramid is the SSD that we use to expand the cache.

In addition to bypassing the write issue, he says that one other benefit to this approach is that in making use of cache, it doesn’t hold the primary copy of the data. Thus the primary data store remains unaltered so there are no concerns about changing how it is managed or backed up. This is what he describes as a complementary technology to SSDs versus something that will reroute how you use them.

McCallum was adamant that despite the fact that it is possible to get data management from an SSD product since the customer already handles her own caching via built-in SSD management tools, read-write manipulation and optimization, there are clear price-performance benefits.

While McCallum focused consistently on the value of their software for SSDs, he claims that this can be used with any type of block interface. When asked where the caching is done his response was clipped since he didn’t wish to give away trade secrets, but he did note that the key is that they’re running the software on the server between the application and the storage—not on top of the SSD itself. From the perspective of the application and storage though, this is all transparent. Suffice to say, McCallum is claiming that if there is a block interface, there is room for his software.

He repeated that VeloBit’s software solution aims to optimize the read and write performance with emphasis on SSD acceleration, although it can speed up a purely disk-based system as well.

One might guess that there could be potential conflicts with running a software-level optimization when there are other manipulations being made to the same storage medium. He says that since they are sitting above the storage medium this is not an issue

This might lead one to believe that this is the part where he announces that to get these price-performance increases means you need to be tied to their own supplied SSDs. His answer to this was somewhat evasive on the partnership front since he admitted that indeed, they would branch into the hardware sphere, but he was adamant that they were not a hardware vendor and were not going to be selling SSDs or other storage devices.

MaCallum couldn’t offer benchmark data to give us a sense of the kind of price-performance improvements, but said they would be publishing figures at some point. However, he says, even though we are lacking some numbers to verify these claims, in their comparisons against the industry-leading SSD and less expensive ones, the results were a combination of price and performance improvements of an order of magnitude.

This leads to the question of whether or not this is a bid to replace a Fusion-io system for example. He says that is one option but even still, if you use the VeloBit solution on top of a high-performance SSD the order of magnitude improvements on price and performance can still be realized but it makes more cost sense to simply use cheaper SSD options.

With Fusion-io, Virident, Texas Memory Systems, and Micron all boasting faster read performance McCallum claims that their VeloBit technology will still prevail. This is because they are operating a different layer, he says. “Look at a traditional storage systems; anytime you can put a cache in front of it, it goes faster—it doesn’t matter what the storage is. The other part, with any SSD, is that it will always be faster with reading than writing. If you use it for read mostly, it will simply be faster.”