For several years now, we've been hearing about how SAN technology will revolutionize the IT world. In contrast, NAS hasn't been anywhere near as hyped; nonetheless, it continues to gain widespread acceptance while SAN is still at the starting gate. Make no mistake. SAN and NAS are real, relevant technologies that will play a role-both independently and together. But the industry keeps chan-ging definitions, making it harder and harder for end users to figure out what's really happening.
By Steve Duplessie
I have a friend who works for a Network Appliance reseller. I asked him how NetApp can continue to get away with telling everyone that NAS-based file serving is faster than locally attached storage. He replied, "It's faster over the network." When I gave him my best "Are you kidding me?" look, he said, "It's always faster."
My friend's statement is entirely untrue, unless we're comparing a souped-up Net-App filer against a Sparc 10 configured with 14-inch CDC drives from 1983. But the point is that people believe it. NAS can be faster, but it isn't necessarily faster. An appropriately tuned, sized, and cached disk array attached directly to a database server will almost always outperform fetching data over a network. If it doesn't, you're doing something wrong.
Another NAS misconception is that it's a new market. NAS is a storage device that users read and write to over the network as a "shared" or NFS-mounted file system. In other words, a NAS system presents storage devices via the network as local devices. NAS devices are capable of handling concurrent, heterogeneous requests from NT, Unix, and even NetWare clients. A lot of non-marketing types might call this a file server, which is hardly a new concept.
Analysts claim NAS could be a multi-billion dollar market within a couple of years. Guess what? NAS was a multi-billion dollar market in 1985.
Don't get me wrong; I'm not taking anything away from Network Appliance or any of the other NAS vendors. Matter of fact, they have done a tremendous job of building a better mousetrap-it's ok to buy their box; just don't buy all the rhetoric.
Auspex was the first to take advantage of a dedicated NFS "appliance," but NetApp came in with an even better mousetrap and made everyone take notice. NetApp has won the battle to date because they built a smart, simple, self-contained system that performed thousands of NFS operations per second. Compared to the traditional Unix server vendors, most notably Sun, NetApp had a much faster, cheaper, and simpler box that could offer network file services in Unix environments. It's no wonder they sold them by the truckload.
It's not just Sun that missed the boat here. Compaq, IBM, and HP have yet to capitalize on the NAS trend. These vendors simply have to come out with real products, even if they repackaged existing gear. Then they have to focus efforts on learning how to sell it.
What happened to Auspex, the top NAS player just a few years ago? The reality is they were caught off guard as NetApp hammered them with a smarter technology play: off-the-shelf components. Auspex never recovered from their high-cost, hardware-centric, large-system mentality, although their new box-the NS2000-has some promise. Auspex has been dogged by poor foresight and time-to-market problems. Their only hope is to play the high-end game that NetApp has yet to enter in earnest. Of course, that pits them against EMC. Enough said.
There are myriad low-end NAS players in the game now. The likely winners of that war will be the disk drive vendors, since drives represent the major cost of the system. Maxtor, Quantum, and Western Digital have low-cost NAS boxes, and the other drive manufacturers are sure to follow. Look for fallout and consolidation among the rest of the low-end manufacturers and integrators. There won't be any room for vendors who don't own technology.
The good news for the NAS market is that the big players are paying attention to NetApp's success. EMC sold $150 million worth of NAS products last year, and I'm not sure any of the sales people even knew what it was. This year they are focusing heavily on NAS. Now that they own Clariion, expect EMC to enter the midrange, NetApp's bread and butter.
Even tape library vendors are in the NAS game now: ATL and ADIC, for example, have NAS tape libraries, making it easier for users to simply plug-and-play at corporate and remote locations.
SAN and NAS
Where does SAN fit into the NAS equation? Put simply, if your application executes at the desktop, use NAS. If your application executes at the server, use SAN. This is a gross generalization, but it applies to the vast majority of situations. If you need file sharing, go with NAS. If you need disk sharing, go with SAN. Eventually, SAN and NAS will blend together.
Look for NAS vendors to implement SAN technologies. NetApp already uses Fibre Channel disk drives in its filers. They recently joined with Fibre Channel switch-vendor Vixel, library vendors ATL and Spectra Logic, and backup software vendors Legato and Veritas to solve a big problem for NetApp customers--backup.
To date, the only way to back up a NetApp NAS device is over the network (which is impossible when you have 12 filers and 2TB), or by attaching a library to each filer (which costs big bucks). Recognizing the problem, NetApp and Vixel got together to figure out how to marry NAS front-ends with a backup-specific SAN on the back end, allowing multiple filers to share a single larger tape library--at very fast, 100MBps switched speeds.
SAN and NAS will continue to be more tightly intertwined, although you'll still hear vendors telling you it's one or the other. Look for Cisco and/or Nortel to cloud things up even further when they come out with SCSI and/or Fibre Channel over IP in their routers and switches.
Some NAS bigots are convinced that SAN is a bunch of hot air. I'm not one of them. Network advancements will continue to help everyone--10Gbit Ethernet will not only offer a fat pipe, but will also do header conversion on the fly. SAN technology, however, will succeed because even NAS boxes need to talk to disk and tape sooner or later, and there is no faster, better way to do that than with a SAN.
Finally, look for devices to become more intelligent. You'll see disk-array "pools" that have direct connections to Fibre Channel fabrics at the same time they plug into 10Gbit Ethernet--automatically speaking whatever is spoken to them. The "hybrid" SAN-NAS configuration, which is beginning to appear, is the trend of the future.
Steve Duplessie is an analyst with storage research firm The Enterprise Storage Group (www.enterprisestoragegroup.com) and can be reached by email at firstname.lastname@example.org