The Beginning of the End for SANs?
Let's say you are manager of a top-tier enterprise data center replete with all the usual trappings: multiple server racks, state-of-the-art SAN, sophisticated intelligent networking and a high degree of virtualization.
Naturally, you are interested in cheaper, more effective solutions, provided they are robust enough to handle your load and integrate with your legacy environment.
Now imagine yourself as the CIO of a start-up enterprise building data infrastructure from scratch. Would you choose the traditional data center architecture described above, or would you opt for a more modular approach in which, say, the storage media may be a bit more expensive but you won't have to deal with that expensive SAN?
This is the question surrounding one of the more significant battle royals brewing in IT this year. It involves the way in which solid state storage and high-speed interfaces like PCIe can be used to place storage resources closer to the server.
On the one hand, you have EMC, which recently launched the results of Project Lightning, now known as the VFCache system, that places NAND Flash cards at the server array to act as high-speed cache for top tier applications. The system is said to boost I/O performance a staggering 4,000-fold while reserving traditional SAN infrastructure, which still makes up the bulk of EMC's revenue, for less critical applications. The system will be followed up by Project Thunder later this year, which calls for PCIe-based NAND storage appliances capable of capacities up to 15 TB or more, but connected to server farms through high-speed, and high-cost InfiniBand links.
To a number of smaller storage vendors, however, the chief question in all of this is, "Why bother with all that storage networking at all?" Led by Fusion-io and its ioMemory subsystem, these upstarts are pitching on- or near-server solid state storage environments that provide not only a more flexible storage environment that is more in-tune with the fluid data dynamics of virtual and cloud infrastructures, but can be built at a much lower price point and operated at lower TCO than traditional SANs.
We're not talking just cache here, but complete storage environments built on modular infrastructure. Indeed, it doesn't take much to imagine what life would be like without storage controllers, HBAs and the raft of other components that currently populate storage networking environments.
These types of SAN-less ecosystems are already coming into focus. A company called Nutanix has deployed the ioMemory system in its Complete Cluster scale-out storage solution. The systems is comprised of compute/storage nodes housing six-core Xeons, up to 192 GB of RAM and 5 TB of storage capacity connected via high-speed PCIe links. The company has already demonstrated clusters of up to 50 nodes, reducing not only cost and complexity compared to SANs, but physical space requirements as well.
Still up in the air, however, is whether these solutions can deliver the kind of storage management functionality that data center operators have come to rely on. It's a fair question, but there doesn't seem to be any reason why they can't. Companies like Assurance Storage are already offering things like automated cache and tier management in NAND/PCIe environments, so it doesn't seem like it would be too much of a stretch to add tools like snapshots, automated back-up and the like.
So it would seem the battle lines are drawn: old-style SANS vs. new-style modular infrastructure. No doubt, support for SANs will continue to be a lucrative revenue stream for EMC and others going forward, but the real question is which architecture will capture the lion's share of storage deployments going forward. With lower costs and faster, more flexible operations in its corner, the SSD/PCIe approach is making a strong run at some very entrenched interests.
Arthur Cole covers networking and the data center for IT Business Edge. He has served as editor of numerous publications covering everything from audio/video production and distribution, multimedia and the Internet to video gaming.