Learn about the technologies behind the Internet with The TCP/IP Guide!|
NOTE: Using robot software to mass-download the site degrades the server and is prohibited. See here for more.
Find The PC Guide helpful? Please consider a donation to The PC Guide Tip Jar. Visa/MC/Paypal accepted.
|View over 750 of my fine art photos any time for free at DesktopScenes.com!|
[ The PC Guide | Systems and Components Reference Guide | Hard Disk Drives | Hard Disk Performance, Quality and Reliability | Redundant Arrays of Inexpensive Disks (RAID) | RAID Concepts and Issues | RAID Reliability Issues ]
The Continued Importance of Backups
I suppose I should apologize for the fact that I tend to hound my readers on the subject of backups. Hmm. Nah. :^) Well, I do apologize to those of you who already know to do backups and actually do them, but unfortunately, you by far represent the minority of PC users. Lack of proper backup procedures is risky at any time, but with some types of RAID, especially RAID 0, it becomes riskier than ever.
Most RAID levels use striping, which causes most of the files on the system to be "chopped up" into small pieces and distributed to various drives in the array. This improves performance but poses a real risk to the integrity of your data. If a drive goes on a striped array, "some part" of almost every file in the system is gone, and there's really no way to figure out what is gone. A fault-tolerant array that includes parity protection eliminates much of this risk by allowing a single drive to fail, but a RAID 0 array does not. Since arrays have much lower hardware reliability than individual drives, this means the odds of a catastrophic, near-unrecoverable failure on a RAID 0 array are higher than most people realize. (Data recovery companies can sometimes perform miracles; frankly, if your data is important enough to warrant spending what a recovery service would charge to reconstruct a RAID 0 array, it's important enough that it shouldn't be on a RAID 0 array. An ounce of prevention and all that...)
If you are using mirroring, either by itself or in combination with another technique, your odds of losing your data due specifically to hardware failure are greatly reduced, but they are far from zero. Regardless, there are a host of other problems that could wipe out your data (for more on these risks, see here):
That's not a comprehensive list, but it's good enough to make my point: even a robust RAID implementation does not replace proper backup procedures. The more you can afford to put together a good RAID system, the more important your data is, and the more you should spend on a good backup system.
Next: Data Recovery