RAID-0 Performance

[D-Bone]

Anandtech just did an article entitled "Western Digital's Raptors in RAID-0: Are two drives better than one?" I think the most important part is the final words which I'll quote for you here:<blockquote>If you haven't gotten the hint by now, we'll spell it out for you: there is no place, and no need for a RAID-0 array on a desktop computer. The real world performance increases are negligible at best and the reduction in reliability, thanks to a halving of the mean time between failure, makes RAID-0 far from worth it on the desktop.

There are some exceptions, especially if you are running a particular application that itself benefits considerably from a striped array, and obviously, our comments do not apply to server-class IO of any sort. But for the vast majority of desktop users and gamers alike, save your money and stay away from RAID-0.

If you do insist on getting two drives, you are much better off putting them into a RAID-1 array to have a live backup of your data. The performance hit of RAID-1 is just as negligible as the performance gains of RAID-0, but the improvement in reliability is worthwhile...unless you're extremely unlucky and both of your drives die at the exact same time.

When Intel introduced ICH5, and now with ICH6, they effectively brought RAID to the mainstream, pushing many users finally to bite the bullet and buy two hard drives for "added performance". While we applaud Intel for bringing the technology to the mainstream, we'd caution users out there to think twice before buying two expensive Raptors or any other drive for performance reasons. Your system will most likely run just as fast with only one drive, but if you have the spare cash, a bit more reliability and peace of mind may be worth setting up a RAID-1 array.

Bottom line: RAID-0 arrays will win you just about any benchmark, but they'll deliver virtually nothing more than that for real world desktop performance. That's just the cold hard truth.</blockquote>
Here's the whole article if your interested in reading:
http://www.anandtech.com/storage/showdoc.html?i=2101&p=1

[Malice]

Yeah, I finally got over myself with the RAID-0 thing. It was fun while it lasted but when I kept losing all my data I got sick of it. I didn't read the article but are they saying that like promise raid controllers and stuff like that are crap but I would imagine if you got a really good HW raid controller it would still be good wouldn't it?

[Ghost]

I suppose the high end caching controllers could make a difference, but I still don't think your going to get a huge speed increase. Mostly the stuff that really needs RAID 0 is video. After all the difference between being able to write to the HD at 20 fps and being able to write at 30 fps is huge.

[r0cc0]

Not sure I like this article. I went back and read the whole thing mainly because fo the line that said, "..the reduction in reliability, thanks to a halving of the mean time between failure, makes RAID-0 far from worth it on the desktop."

According to their logic they "halve the mean time between failure" any time you have two hard drives in your computer. The only difference is with RAID 0 when a drive fails you lose all your data, where as with JBOD you would lose whatever data you had on the failed drive. This is just a ridiculous statement.

Second I saw a huge difference in performance during installation of games, between RAID 0 and none RAID 0. PC Halo loaded in around 2 minutes with the RAID 0 and around 10 - 15 minutes without.

I have heard that there is a slow down with reading since files are scattered between discs and it takes longer to locate the files.

[Malice]

Well I did the RAID0 thing for a while too and actually they are pretty much right on. I lost one of my HD"s and bam, lost everything so yes it really does reduce your reliability. Although, a graduate of Probability and Stats last semester, you are right, it does not actually halve it but it does make a big impact. For example, if you have a probabilty that one drive fails per year is say 10%, the probability that 1 drive out of 2 fails is 1-.9^2=.19 or 19%. So you go from 10% to 19% likelyhood of losing your data since you only need one drive out of two to fail for it all to disapear. I'm glad you are seeing such great performance gains but I saw only marginal improvements, albeit some. But I am curious you said it went from 2 minutes to 10 - 15 minutes. Was this on the same system with the same drives, just running singely? Also was it originally on an old load of windows with a somewhat fragmented disk? There are lots of factors and you are boasting some pretty nice improvements there. You might have a kick ass RAID controller. As for me it's RAID0+1 or RAID5 only from here on out. As for read speeds, if I understand it correctly that would only be slow for frequent small reads but for large files it should be faster.

[Dante]

damn malice... you a college dude or something spewing out all that math crap? ;)

[Malice]

Yep, at least I'm getting my money's worth.

[r0cc0]

So it was the exact same system before with a brand new install of XP. One of my HD's crashed and I had to reload the OS and all my games on the now single drive, while I waited for the replacement to come. This is when I noticed the difference in performance while installing Halo. I have received my replacement drive so I will once again be reinstalling everything. I can verify the results of the Halo install again.

Also my point was that it doesn't actually increase the mean time between failure on a HD. Your chance of having a HD failure does increase since you have more discs. However it would be the same probability whether its JBOD or RAID. Depending on how you have your data setup, it could still be as catastrophic on JBOD as it would be on RAID. For instance OS on one disc, files on the other. You lose the OS disc, no big deal, just reinstall. You lose the data disc and your hosed if you don't have a backup.

I guess my main argument was that they were saying that RAID increases the chance of HD failure. Its not really RAID that increases it, its adding the second HD that increases it.

My RAID controller is the onboard INTEL controller. I have the D875PBZ mobo.