|MICRO CENTER: COMPUTERS AND ELECTRONICS|
|In The Lab
RAID & NAS
What do you use your computer for? If you are like me, it probably involves multimedia in one form or another. By multimedia, I mean digital photos, music, video as well as text and other raw data. If you have a Media Center PC, or even just a TV tuner / video capture card installed, I probably don't have to tell you how big some of these files get. Unless you are sacrificing the capture quality, chances are that the TV shows you record are just about the same size as commercial DVDs; roughly about 4 GB for each hour of video. If you tend to record many TV programs for later viewing, you probably have also noticed how small that 160 or 200 GB hard drive really is.
Expanded storage options
A second solution is to add some sort of external storage unit such as a USB or Firewire drive. An added advantage is that these drives are portable and can be moved around and connected to other computers in the home or business. This is particularly useful for backing up or transferring very large files between systems, among other things. Drives like the Maxtor "One-Touch" series or the Buffalo Technology DriveStation include software for managing regular backups of critical data. In addition to complete USB or Firewire external drives, don't forget about external drive kits. Taking one of the external kits and installing one of your old hard drives can create an inexpensive, high-capacity storage device.
For a third solution, you could consider adding a server to your network. A basic server is nothing more than a single computer system that is sharing its storage or printer resources over the network. But, servers can also be used for much more, including managing network connections, such as a router or firewall, making web content available to the network, managing email and more. Commercial servers often differ in that they include fault-resistant or redundant hardware such as dual power supplies and RAID enabled hard drives. I'll come back to RAID in just a bit, as soon as I get done throwing around some more acronyms and jargon...
A fourth type of external storage is what is called Network Attached Storage (NAS). Very simply, this is a set of hard drives with a minimal computer-controlled network adapter that shares its storage over a network. Some of these devices, like the Buffalo Technology TeraStation or their LinkStation, can also share devices attached to its USB ports including external USB drives and printers. The Buffalo TeraStation has the advantage of providing fault resistant storage across four hard drives in the unit. The default configuration for a unit with four 250GB drives is in a RAID 5 configuration where information and error correcting information is spread across all four drives. The available storage works out to about 750GB in this configuration. The TeraStation can also be configured to appear as four 250GB drives, a single 1000GB drive (1000 GB is 1 Terabyte, hence the name TeraStation), or as two mirrored 250GB drives.
Security and / or performance through RAID
Some of the more common implementations of RAID schemes follow:
Some RAID controllers also support combinations of the RAID schemes, such as combining the increased capacity of RAID 0 with the fault tolerance of RAID 1. This involves creating either a striped set and then mirroring it to another striped set (sometimes called RAID 0+1), or by taking a two mirrored sets and striping them together (sometimes called RAID 10, RAID 1+0 or RAID 1&0.)
To be able to manage your RAID set from within the OS, additional drivers and or software utilities must be installed. This can create additional steps if you are trying to install your OS to a hardware supported RAID controller; you may have to load the RAID driver during the installation process for the setup utility to detect and access the drive set. For example, when installing Windows XP, you must press F6 early in the setup process to add SCSI or RAID driver support before the target drive can be formatted and files copied. Controllers that support non-destructive conversion to RAID sets can simplify the process by allowing you to install and configure your system on a drive, and then add another drive and create a mirror at a later date. These same controllers usually will support non-destructive breaking and rebuilding of mirror volumes which can be useful in archiving the entire drive image, or quickly replacing a failing drive. If the controller does not support these features, you will have to back up all of the data from the good drive; (break the mirror, if necessary), replace the failing drive, recreate the mirror and format the set, and then restore your data to the new mirrored set.
Keep in mind that RAID schemes (other than RAID 0) are methods for increasing the reliability of the storage hardware by adding error detection and correction features to the read and write process. RAID does absolutely nothing to protect you from viruses, worms, Trojan horse programs or even accidental deletion of data. All it does is reduce your chances of data loss from a hard disk hardware failure. You still need to take precautions in day-to-day use of your computer by using a good anti-virus program, a firewall and some common sense. In addition, you should also maintain backups of any critical data or files contained on your system or network storage.
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