RAID: Not Such a Clever Idea for Your Home PC - Does Technology's Go-Faster Stripe Actually Add Speed?

The issue with RAID 0 has always been that splitting data across two hard disks inevitably resulted in doubling the chances of data loss via hard disk failure. It is the logical downside to a single striped volume spanning two physical drives that if either disk fails no data is recoverable. The risk rises as more drives are added to the array. Don't let the "R" in RAID mislead -- in a RAID 0 configuration there is no redundancy.

Associated with a higher risk of data loss RAID 0's only attraction remained its perceived faster speed, and faster speeds are always welcome. It had long been the gripe of video editors that standard hard disks weren't fast enough for video. When technology improvements like higher spindle speeds, larger caches, Tagged Command Queuing (TCQ) etc. brought phenomenal speed increases to the storage arena video editors complained that speeds still weren't sufficient for advanced video work and the handling of higher quality footage - like 10 bit video. Video isn't the only application that takes all the speed that's thrown at it and asks for more. Lots of other applications could use more speed from the IDE subsystem. Since storage speed improvements just haven't matched improvements in other areas like CPUs and GPUs -- and disk reading and writing is still the bottleneck in most modern PCs -- SIs, VARs and even home PC users having been flocking to the technological amphetamine that is RAID 0 instead of spending some time learning how they can optimize their hard disk performance.

What made striping even more attractive was the scalability of the technology. In theory throughput keeps getting faster and faster just by adding more drives to an array.

But very little of that is true. RAID 0 does not always make for more speed. In fact striping may not make the blindest bit of difference to the speed of the average home PC!

Reputed technical websites like StorageReview have often commented that gains on RAID 0 vs single hard disk are minimal at best. Test after test by some of the most reputed technical websites have proved that RAID 0 does not significantly improve desktop performance. Not even with the far higher risk of a four disk RAID 0 array. Seriously! Very few home users tend to be aware of all these technical studies and those that do very often pooh-pooh the idea that the RAID configuration they spent a lot of money on is not actually running faster.

If the claim that RAID 0 is not all it's cracked up to be sounds illogical then it's worth taking the time to read the reviews. A search in Google should lead you to them. Except for a few limited high I/O activities like video editing -- and the typical application benchmark -- the speed gains are almost non-existent. For the average PC user RAID 0 is as useful as a rear spoiler on an 800cc car. It looks good, it sounds impressive but it don't do nuffin'.

RAID 0 has been striped (pun apologies) of its only virtue, speed. If striping increases risk of data loss but provides no speed gains worth writing home about -- why is it still so popular? Well, myths are not easily dispelled. Marketing gumph designed to sell motherboards with RAID still boast about massive speed gains to be achieved. Hard disk retailers would rather sell two disks than one. And there's always product differentiation -- our PC is faster because it has RAID. Users are rarely told the other risks because risk warnings don't shift stock.

Other risks? Yes, there are other risks. Isn't drive failure considered not a very likely mishap? The other risks are even bigger monsters and take the risk-reward ratio firmly toward not using RAID. But hardly anyone seems to know about these risks so they don't get discussed often. More later...

Next: RAID 1 - Give up the ghost? >>
 

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