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2009059 · Dec 30, 2005, 08:54 AM

Hi,

I'm wondering which config will give me the fastest speeds. Two 400 gig, 16mb cache 7200RPM drives RAIDed or the 400 gig with a 72 or 36 gig 10krpm Raptor? I use this machine for video editing, photo editing, school stuff, games, pretty much everything.

jebjeb · Dec 30, 2005, 09:46 AM

Originally Posted by 2009059

Hi,

I'm wondering which config will give me the fastest speeds. Two 400 gig, 16mb cache 7200RPM drives RAIDed or the 400 gig with a 72 or 36 gig 10krpm Raptor? I use this machine for video editing, photo editing, school stuff, games, pretty much everything.

Worth looking at this BareFeats article.

mduell · Dec 30, 2005, 08:02 PM

What matters more to you, seek time or throughput?

2009059 · Dec 30, 2005, 08:34 PM

Originally Posted by mduell

What matters more to you, seek time or throughput?

I'm guessing RAID would be throughput, raptor be seek time? I'm leaning towards RAID rightnow, found a pretty good deal on ebay.

new newton · Dec 30, 2005, 09:22 PM

More to the point, what do you need RAID 0 for? It's reliablity is terrible. If you don't have a purpose for it, you shouldn't use it.

G5man · Dec 30, 2005, 11:50 PM

Do you need the storage more? Or do you need speed?

mduell · Dec 31, 2005, 02:53 AM

2009059: You got it. I think a 74GB Raptor and a 500GB Hitachi is a better solution for everything except video editing (where you'll want the space and the throughput). So my answer depends on how much you're doing video editing compared to other things.

new newton: It's not that bad (slightly more than twice the probability of a single drive failure) and even without RAID you should be making regular backups.

Cadaver · Dec 31, 2005, 11:33 AM

Originally Posted by new newton

More to the point, what do you need RAID 0 for? It's reliablity is terrible.

Its failure rate would be exactly twice that of a one-drive system.

jebjeb · Dec 31, 2005, 12:31 PM

Originally Posted by Cadaver

Its failure rate would be exactly twice that of a one-drive system.

I'm not sure about this, but what about the added variable of the software (or hardware) RAID controller failing? I agree that the use of two drives exactly doubles the likelyhood of disk failure but a single drive does not have to contend with a RAID controller deciding where to put data on the drive. Although, a single drive still has a controller so maybe this point is worthless.

2009059 · Dec 31, 2005, 02:47 PM

So reliability and space I would go for raptor and RAID for speed? I guess I should go raptor then. Thanks everybody.

mduell · Dec 31, 2005, 04:05 PM

The RAID will give you higher throughput and more space.
The Raptor and another drive will give you marginally better reliability and lower latency (for files on the Raptor).

new newton · Dec 31, 2005, 04:45 PM

Originally Posted by Cadaver

Its failure rate would be exactly twice that of a one-drive system.

It's been a long time since my last statistics course, but that's incorrect. You're combining chances of drive failure, not doubling them. Not only that, but drive failure isn't the only cause of a RAID 0 failing. Data corruption can lead to pretty nasty results for the whole array, not just a few files.

RAID 0 is great for when you need a certain level of performance that can't be had with a single drive, and you can't afford a more reliable solution. It's a really, really bad idea for the typical user that doesn't understand the risks and doesn't actually need the performance.

If my data was less important than speed--and the speed was required--I'd use RAID 0.

Cadaver · Jan 1, 2006, 08:19 AM

Originally Posted by 2009059

So reliability and space I would go for raptor and RAID for speed? I guess I should go raptor then. Thanks everybody.

I think I had read that 150GB Raptor drives are coming shortly. Something to think about.

2009059 · Jan 1, 2006, 08:22 AM

Originally Posted by Cadaver

I think I had read that 150GB Raptor drives are coming shortly. Something to think about.

thanks for that, I'm going to wait for those babies.

doublep · Jan 4, 2006, 12:11 AM

The Raptor 150 Go review can be found here:

http://www.storagereview.com/article...500ADFD_1.html

P · Jan 4, 2006, 12:08 PM

Originally Posted by new newton

It's been a long time since my last statistics course, but that's incorrect. You're combining chances of drive failure, not doubling them. Not only that, but drive failure isn't the only cause of a RAID 0 failing. Data corruption can lead to pretty nasty results for the whole array, not just a few files.

RAID 0 is great for when you need a certain level of performance that can't be had with a single drive, and you can't afford a more reliable solution. It's a really, really bad idea for the typical user that doesn't understand the risks and doesn't actually need the performance.

If my data was less important than speed--and the speed was required--I'd use RAID 0.

I agree about the risk of data corruption from RAID 0, but I do think that the statement about the failure rate was correct. You are talking about the risk that a drive fails, over a timespan from now to infinity. In this case, I think it's more appropriate to use a Poisson distribution to estimate the number of failures over time. Since the variables are independent, the failure rate is actually doubled - provided I remember MY statistics correctly.