What Storage Folks do not get about Fusion-io

From Wikibon

Revision as of 02:22, 23 April 2011

#memeconnect #fio

Fusion-io and other vendors who provide flash storage through the PCIe interface are often criticized by storage companies as having ‘no legs,’ implying that they will be taken out by larger players (either a storage company or a flash technology company) as the market matures. Storage folks in particular talk about the imperative that data should be shared across all the servers, so that the resources can be shared.

What many storage folks don’t get or at least admit are the following:

1. Storage sucks. Storage is painfully slow. The system is waiting for spinning, mechanical rust. This arcane approach, which has been in place for more then five decades, is forced on systems architects and application developers. Access to mechanical storage is so, so slow – measured in milliseconds. Even the use of flash storage technologies that use the ancient channel and storage protocol paradigm are still very slow compared with processor and RAM speeds.
2. From a systems perspective, the only thing good you can say about storage is it’s persistent; except for very expensive RAM storage protected by batteries. This fact has allowed the storage industry to extract rents from users for decades.
3. For two decades, we’ve seen function migrate away from the server out the channel to the storage array. Much of this has been for practical reasons related to sharing data. That’s good.
4. However, the fundamental constraints of the spinning disk architecture remain.
5. Systems and application architects take a different view. For the first time in history, they have the opportunity to have a persistent resource on the “right” side of the channel. Flash storage sitting next to the processor can be regarded as an extension to RAM storage, with the huge advantage that it is persistent. That dramatically simplifies architectures, the operating systems and the database systems. Technical developers are architecting systems where the active data is stored on flash storage next to the processors. If that data is needed, the processing is moved to the node where the data is stored. It’s a shared nothing model that enables data to be spread across nodes and introduces a new sharing model. Of course for the inactive data, there will be a traditional, slow, cheap storage network. Within a few years, most high performance systems will have large amounts of flash storage next to the processors

Is Facebook a Bellwether or an Outlier?

The first designers of these systems are the social medial giants, who have found that systems with traditional SAN architectures cannot provide the power and flexibility required for them to grow. They simply don’t do mega-Web scale. While not everyone agrees, we feel that Web 2.0 leaders are a harbinger to future systems designs.

As Little’s Law implies, look for the queues in any system and apply technology to reduce the bottlenecks. Fusion-io, and maybe some other vendors in this space (e.g. Oracle) have it right. They understand that it’s not about hardware, rather the secret is in IP that allows systems to read and write directly from the processor to flash in a single pass with no cumbersome, multi-phase commits required in traditional storage, file system and database protocols.

A leading example is Fusion-io’s VSL, which is like expanded storage on IBM mainframes; except it’s persistent and way less expensive (e.g ten times cheaper than RAM). Essentially this resource creates huge blocks of addressable data meaning you can design terabytes of address space that scale to incredible levels (i.e. address space limitations are blown away).

VSL is an architecture that maps address spaces in RAM on to PCIe flash storage. Because of this mapping, when you choose to write data it will go directly to the controller via direct memory access. From a software point of view this “expanded memory” is a large virtual resource that enables designers to get rid of 99% of the IOPs. And as the saying goes – “the best I/O is no I/O.”

Will the Whales Swallow the Minnows?

Companies like Intel clearly are going to get into this space in a big way by embedding such technologies into systems design. How will the likes of Fusion-io compete? The way startups always compete. Being first, being fast, getting OS suppliers, database vendors and ISVs to exploit the architecture and innovating.

Does Fusion-io have a window of opportunity? Absolutely. Intel moves architectures at a pace of about every five years. Fusion-io must move faster…much faster. In the meantime, companies like IBM, HP, Oracle and Dell are watching Fusion-io very closely and likely will be introducing their own architectures over time.

We believe this confirms Fusion-io’s vision and increases, not decreases their value.

Action Item: New system architectures are emerging and while shared storage models will remain, new thinking about systems design is presenting radical opportunities for application designers to deliver order of magnitude increases in performance and application functionality. Fusion-io is leading the way and observers should pay close attention to its moves. While execution will ultimately decide Fusion-io’s fate, its technical vision is spot on for cloud-scale applications.

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