MrMagoo wrote on Apr 10th, 2006 at 2:48am:I'm interested in why you say that RAID sucks.
As I have set up RAID of many types over dozens computers, I have several emperically derived opinions:
First some terms: RAID 0 I'll call stripe, RAID 1 I'll call mirror, RAID 5 I'll call "pairing" short for collective parity backup, RAID 10 striped & mirrored, and raid 50 striped and paired.
Also important to know are throughput data transfers, like how long to move a video file, vs seek time, like how fast can you find a file, and random access time, like how fast can it move all over the drive collecting bits and pieces.
1) If you have a slow proc, slow hd's, and want to stripe to increase speed, bad idea. In this case you are likely going with an inexpensive software based raid controller that will suck even more proc power you don't have and while your throughput will be faster, your overall sense of performance will not be a net gain.
2) If you have sufficient funds, fast hardware, and want it faster, than striping IS great as it increases throughput, but not random access or seek times. So loading, moving or copying large files will see a boost, especially with good well matched hardware. I recommend automated daily back up to other disks outside of the computer (like a networked massive hd) so the statistically increased chance (2x for 2 drives, 8x for 8 drives etc) of losing the data is of no consequence.
3) If you have a mission critical array that you still want as fast as possible, I personally went with striped and paired. Using 8 raptors with hot swapable bays (my budget for this project allowed for $2k. More drives and using Atlas's as would have been faster/bigger/better). I striped 4 pairs doubling throughput and I was able to get 75% capacity storage, but I was still super safe by pairing. Could the budget have afforded the 12x sata card and 4 more drives, I would have had 83% capacity. Raid 5/50 is very cool.
4) if money is no object and speed is all there is go with SSD (solid state drives). These are primarily used in the military (where money is no object) and obviously get VERY expensive quick - $30k for a hard drive is the norm. Their throughput is a lot faster than normal drives, and still a little faster than the 15k atlas's, but where they really rock is seek times and random access – they are several orders of magnitude faster as the mechanical limit imposed on the normal hd's are removed. Entusiast level drives are hitting the market like Gigabye i-Ram, DDRDrive and Hyperdrive IV, but cost is still huge.
When we wish to speedup our computers, it is imperative to keep in mind where the bottleneck is. If you had 1 hr commute to work on the Autobahn, upgrading your Yugo to a Mercedes would significantly improve your commute time. Go to a Mclaren F1 and it has major improvement again. But say you commute at the worst possible time in LA, what difference does a faster car make? An even better analogy is my commute. Fast roads but a lot of stop lights. Most of my time is at stop lights. If I double my speed, I only improve the time between the stop lights, so it takes me 22 min instead of 25 min, even thought I’m driving 2x as fast. With most computers, HD's are the bottleneck, but not always. Even when they are, what exactly is the bottleneck about the hd? Is the random access? Seek time? Throughput? It varies by application. Certainly speeding one thing up doesn't hurt, but if that wasn't our stop light, it might not make a difference.
Albeit fringe tech, it is perfectly acceptable to stripe SSD's, increasing the speed of SSD's "slowest" aspect. As a true technolust guy, I plan to stripe a pair of 4gb iRams for the OS portition of my next computer. I have heard of a sub 5 second windows load time. Oh baby.
ALL of this was to answer the question - Why would someone say RAID sux. (damn im longwinded) I would guess because they thought throughput was their bottleneck, went through expense and trouble of striping some drives, and found out throughput was in fact NOT their bottleneck.
Just my $0.02.
Peach.