Raid 0: Blessing or hype?

Yoeri Lauwers writes "Tweakers.net investigates matters a bit more clearly and decides that AnandTech and Storagereview should think twice before they shout that "RAID 0 is useless on the desktop". Tweakers.net's tests illustrate the contrary"

I've used RAID 0 in the past

[Anonymous Coward]

I don't care what tests people have done or what benchmarks they're spouting off, RAID 0 works.

I used to have a system which used relatively cheap 5400 RPM drives in a RAID 0 array. There was a quite noticable difference when not using RAID 0. When using 2 or 4 drives the system was damn fast even though the drives were individually slow.

I don't even read these articles. I know it makes a difference.

Desktop performance.

[Zorilla]

My computer is over three years old (P4 1.7 GHz upgraded to 386 MB of RAM from 128) and I've found that the slowest technological advancement seems to be hard drive throughput. This definitely reveals itself because of the fact that games like Doom 3, Far Cry, and Painkiller are all perfectly playable on my computer, but the latter two games take an unbearably long time to load. When I build my next computer, RAID 0 is one of the things I will be looking at, because I absolutely hate waiting more than 5 seconds for a game to load.

(Yes, I'm aware that only 384 MB of RAM is slowing load times via virtual memory swapping as well)

Theoretical versus Actual

[ergo98]

A common theme, revisited several times, in the article is that the other conclusions were wrong because they used low-load testing.

"A safe conclusion would be that a Business Winstone 2004-benchmark alone is not a good starting point when testing RAID 0 performance. On the contrary: to have some reliable tests, we will need to put heavy loads on the array."

In essence, if my understanding is correct, they're saying that the value of a RAID 0 setup is under constant extreme loads, not the loads created by business applications or games. Isn't this entirely the point of the articles in question - That given the sporatic, generally light load of even power users, RAID 0 is not really that beneficial (as random access plays even more of a part than gross throughput)?

Even under perceived heavy I/O loads, the reality is often that the hard disk is under-used - I occasionally compress videos from miniDV to DVD, and my CPU would need a four or five fold increase in speed to even begin to put pressure on the single 7200 RPM hard disk.

Re:Sure, RAID 0 is great for data loss!

[jackb_guppy]

Actually closer to: 0:bebedt 1:y y aa

Re:Sure, RAID 0 is great for data loss!

[jackb_guppy]

The same arguement goes for mirrored as well.

Have you ever had a "sick" drive in a mirrored array? When that drive is working, it is giving out bad data that is then being written to both drives during the update/write back. Then you have coruption on two drives instead of one.

The "safe" setup is Raid-5, but if you loose 2 drives you lost all...

A service tech loose his balance while replacing a down drive in a HOT Raid-5. He fell backward while squating pushing in the new drive. He grabed another drive in the same array to stop his fall, and pulled it out... Every bad shutdown for a production system, and a very long recovery.

Now service techs are required to sit in chair when changing a drive below chest hieght.

RAID Cost?

[Anonymous Coward]

How much does raid cost, how come I never heard of it for home users, just for large institutions?

I want RAID now, it sounds like a good idea, esp. if I get one that had redundancy, is it expensive?

Re:I use RAID 0...

[shokk]

For enterprise wide capability, combine the drive letter mappings with Active Directory Dfs. Gives you an automounter type capability centrally managed across the domain tree.

Re:Sure, RAID 0 is great for data loss!

[Tassach]

Raid 0 is no different to having a single disk for most practical purposes.

WRONG. RAID-0 dramatically INCREASES the likelihood that you WILL have problems. Instead of having one physical mechanism to worry about failing, you have two or more. In a given time span, the probability of 2-drive RAID-0 array failing is FOUR times that of single drive; a 4-drive RAID-0 array is SIXTEEN times as likely to fail as a single drive. It's an inverse square relationship (1/N^2) because the failure of one drive kills the whole array.

If you expect 36 months of reliable operation from a single drive, you can only count on 9 months of reliable operation from a 2-drive RAID-0 array built from those same drives. Hope you enjoy restoring from backups, because you're going to be doing it at least four times as often.

Re:I use RAID 0...

[boaworm]

Yep, totally agree. Do you remember the LaCie 1.6GB FW-drive [lacie.com] released to market a few weeks back. This is nothing but four IDE drives in a raid configuration, and it's not redundancy raid...

I really wonder what the expected lifetime is on such a device. Sure you can replace the broken drive, but you should probably get the same model to replace the broken with, AND if one has gone down.. how long 'til the next one goes ?

Its probably great for things like offsite backups, you run it an hour here, and hour there, but it sure dont seem like a reliable solution to store valuable data on.

Data loss , who cares.....

[Gailin]

Everyone keeps mentioning about the lack of fault tolerance in Raid 0. Personally I do not know anyone who runs a Raid 0 configuration on drives that containe data that would be considered important.

Personally I'm a hardcore gamer, and I run Raid 0 on two WD SATA 36G Raptors. These drives are used for my system drive and where I install my apps. Anything that is important is shoved off to a set of big, slow IDE drives that are running in a Raid 1 configuration.

So MTBF really doesn't matter to me, as when one of the drives fails it takes me a grand total of 18 minutes to reinstall Windows XP (timed it), add in another hour for driver configuration and updates, and I'm back to where I was before the drive failed.

Raid 0 can work out just fine, as long as your realize its limitations and store your data accordingly.

Gailin

Re:RAID Cost?

[Theatetus]

I want RAID now, it sounds like a good idea, esp. if I get one that had redundancy, is it expensive?

Well, RAID is not always redundant. The RAID talked about in this article isn't redundant. In fact, it's "less" redundant than a drive with 0 redundancy, since each drive is now sensitive to failures in the others. It's negative redundancy (in fact, RAID 0 is often called "not true RAID", since the "R" in RAID stands for "redundant".

And, yes, a good RAID controller is expensive and often not available for a PC chassis & mobo.

Redundancy vs ????

[xyloplax]

Everyone is concerned about redundancy and increased probability of one drive failing the more drives you have. Yes. If you are comparing it to RAID 1, RAID 1+0 or RAID 5. But we are talking desktop systems. You, know, the ones with single drives. So you already have no redundancy to begin with and now you are adding speed. And a somewhat increased risk of drive failure. However, I already have 3 separate drives on my system, so I am only going to get the speed benefits.

Re:I use RAID 0...

[giberti]

My LaCie 320Gb drive (2 seperate disks) died after 6 weeks. They did however replace it, only cost me shipping, however, I lost a good bit of video I had encoded. More of a frustration than a true loss since I still have it all on tape.