There's a lot of talk these days about the so-called convergence of NAS (Network Attached Storage) and SAN (Storage Area Network) technologies. With enterprise storage needs growing at 52 percent per year (according to Forrester Research), IT organizations (ITOs) need to be able to divine the coming trends to be adequately prepared, and to avoid dead-end technologies. In part, this means moving away as quickly as possible from direct-attached storage (DAS). But which of competing storage technologies SAN and NAS will provide the best bridge to the future?
The two technologies differ in the way they handle data. NAS works at the file level, connecting to the server via the Ethernet network; SAN operates at the block level, using SCSI commands over Fibre Channel connections. The advantage of NAS is that it's relatively easy to set up and manage. The primary advantage at this point for SAN is that it takes a lot of traffic off the main Ethernet network.
There are a whole host of new technologies that will influence the shape of things to come. Among these are iSCSI (Internet SCSI), FCIP (Fibre Channel over IP), and SoIP (Storage over IP), all of which aim to somehow translate their normal transport architectures into IP packets for transmission. Up to now, the latency and unreliability of TCP/IP has been the biggest barrier.
Assuming this can be solved--and IBM and other vendors are offering iSCSI products already--then the basic architecture of the two technologies starts to blend. Keep in mind that no one expects to see actual convergence products available until 2004 at the earliest, and large-scale adoption probably won't take place until 2005 or 2006.
So the challenge for ITOs is how to prepare existing networks for the coming convergence of storage architectures. Flexibility is the key, and avoiding decentralized solutions that will be difficult to integrate into the new storage network is another distinct tactic. Using the right tool for the right job is always important, and the vast majority of storage demand for most enterprises is for file based, not networked storage, according to Forrester Research. The best way to address this sort of storage need in the short run is using inexpensive NAS appliances. Applications that require maximum performance, such as online transaction processing, are better served using Fibre Channel-based SANs.
Keep in mind that convergence also means that the value to look for will not be found in the transport method, but in the software and management in the server and in the storage network. To focus too much on whether what's being done under the hood is via Fibre Channel, iSCSI or FCIP (or even InfiniBand) is misdirecting resources that could better be used looking at management tools and software.
Given the complexity and confusion surrounding these decisions, many analysts are predicting that more and more enterprises will turn to Storage Service Providers. While it's true that the cost is a bit higher than either NAS or SANs, the headaches are offloaded to a third party, and high-speed optical carriers mean the cost of moving massive amounts of data is dropping dramatically. And although you might consider Storage Service Providers as a possible alternative you may find yourself in a minority position. There's still a way to go on security matters. Denial of Service attacks and other hacker antics inconvenience e-commerce customers. Those same attacks could deny you access to your data and applications and that may just about put you out of business.