By Pat Taylor, Proactive Technologies When several Macs are on the same network, the Mac-to-Mac chatter builds to the point where it becomes a 'broadcast storm' that slows movement of files across the network. November 8, 2004 -- Storage technology is the most critical component of a printing company's digital infrastructure. Historically, "storage" means a disk drive inside a computer or a fault-tolerant array (RAID) directly attached to a computer with a SCSI or Fibre Channel cable. As storage options have gotten faster, more reliable and less expensive, the options have increased. Two of the newer technologies to earn attention in the graphics business are NAS (Network-Attached Storage) and SAN (Storage Area Network). This month, we'll define these technologies and discuss their use in printing and publishing environments. NAS NAS (Network-Attached Storage) devices are essentially disk drives with an Ethernet connection. That is why we call them 'network-attached:" they plug directly into the Local Area Network (LAN) and are immediately available to users on the network for storing data. Some of the more sophisticated NAS devices actually have servers embedded within them allowing multiple platforms (Mac, Windows, and UNIX) to share files on a single volume. The most common NAS devices are simply disk drives in a box which plugs into a network switch, providing affordable storage that is easy to install and administer. Moving large files through a printer's LAN to Network-Attached Storage is like trying to drive a tractor/trailer through a busy school zone. The effective utilization of Network-Attached Storage in our industry, though, is a matter of debate. Many users are quick to snatch up Snap Servers (the most popular NAS product in our industry) because they are inexpensive and easy to use. Unfortunately, this is the end of the NAS value proposition for printers and publishers. You see, we're creative people, and creative people love Macs. We love Apple products because they are beautiful and (along with other insanely great features) Macs are very easy to use. When you plug your Mac into the LAN, it says "I'm here". Macs broadcast their presence to every other device on the network and they do it constantly--which is precisely why they are so easy to use. Other Macs on the network respond to our broadcast with a friendly "I'm here, too". When several Macs are on the same network, the Mac-to-Mac chatter builds to the point where it becomes a 'broadcast storm'. These broadcast storms slow down the movement of files across the network to a NAS device. You can create a mental image of this by thinking of a residential street clogged by the slow-moving traffic in a school zone. It gets worse. We use our Macs to create VERY large files. We have to move these large files through our network during the production process, and "faster is better". Think of these large files as 18-wheel tractor/trailers which need a lot of room to maneuver and move painfully slow in heavy traffic. Consequently, moving large files through a printer's LAN to Network-Attached Storage is like trying to drive a tractor/trailer through a busy school zone. The road is already crowded, and there is no room for trucks. If a truck must pass through, it cannot move very fast. The SAN Approach SANs are purpose-built networks that move big files fast and are particularly well-suited for the printing and publishing business. Storage Area Networks use a different approach. Storage Area Networks (SANs) are constructed using Fibre Channel to build a supplemental network to the LAN (as opposed to using the Ethernet cable that is the LAN). This Fibre Channel network is dedicated to moving big files between servers at twice the speed of the fastest Ethernet. SANs are like the highway 'loops' we build around big cities so trucks traveling through do not clog up the residential roads. They are purpose-built networks that move big files fast, and they are particularly well-suited for the printing and publishing business. Clearly superior to NAS from a performance point-of-view, Storage Area Networks suffer from having a fairly large price tag. By definition, SAN deployment requires us to build a second network. It also requires new skill sets (which means more training), whereas Network-Attached Storage relies on the same skills utilized to manage the LAN. Choosing between the two technologies is commonly dictated by (a) the intended utilization of the storage device and (b) the available budget. NAS devices are affordable 'bit buckets'--cheap warehouse space--for anyone on the network who has the time to drive through traffic for the files they need. SANs are usually deployed by organizations that have multiple terabytes of data to manage, and to whom fault-tolerance and transfer speeds are high priorities. Knowing the strengths and weaknesses of each technology will help you decide which is best for you. It may be that you need a bit of both.