RAID at Platter Level

[Fattoxthegreat]

So I was wondering. Why wouldn't we make hard drives with built in RAID levels at the platter level. By this I mean having a 4TB hard drive but separate half of its capacity as a RAID1 of itself so you end up with a 2TB extra secure hard drive (two 1TB platters in RAID1 with two other 1TB platters)?

 

This thought crossed my mind when I looked up the specs of the first 6TB hard drive to hit the market. I saw it had 7 platters in it instead of the anticipated 6. So I was curious what that oddball platter was doing in there, then it hit me; "What if there's some sort of RAID going on in there?"

 

Now, the obvious first reaction to this is "What's the point?" Valid concern. But the way I see it, redundancy RAIDs (1, 5, 6, etc.) are there incase specific sectors on specific platters go bad, and typically these hard drives are going to be in the same system. So if a computer falls off a desk or something, it's taking all the drives down with it anyways so this way, it at least saves space.

 

I can imagine this being far more of a good idea once 10+TB HDDs become more commonplace and instead of buying 2 at half the capacity, you could buy one big one and RAID it with itself.

 

Obviously this idea had data redundancy in mind first and foremost, but I can't see why Striping a hard drive with itself would be any less valid of an idea.

 

Why do you think? Is this just the fevered dream of a mad man? Does something like this even exist (I have no idea)?

[FearMe]

This might work with RAID-1 but I don't think it'll work with RAID-0 or something like that.

[bob345]

The way i see it, if a hdd fails, the whole thing fails. not just some of the platters. I doubt it would actually make a specific part of the drive more reliable

[rmac52]

You would need to duplicate every bit of hardware inside the drive to get that to work.  Also you would have to add in a raid controller inside the drive.  I suppose it would be doable but I don't think this would be a very efficient way to design a HDD.

I have taken a fair number of HDD's apart but I'm no expert so I could be wrong on the complexity of adding redundancy to the drive.

[babbaj]

Raid 1 on platters makes no sense

[Fattoxthegreat]

Raid 1 on platters makes no sense

 

Invaluable pontification ol' chap. Care to expound upon this notion?

[KemoKa]

you'd have to have independently-driven reader heads which means more magnets, more complicated construction and therefore a need for high-end precision equipment to build the things, you'd need a much, much more powerful controller to send/receive signals to/from each reader head simultaneously. The final thing, the way I see it, is that RAIDing at the platter levels, based on the above complications, would also make for many more moving parts, increasing the amount of points of failure by an order of magnitude, thereby rendering the entire RAID 1 idea completely pointless anyway.

[IdeaStormer]

First off HDD's are in the platter sense RAID 0, that's how they get the speed. The spindle spins or spindles, and you have at least two heads per platter, one on the top and one on the bottom. Every write, writes to both heads at the same time much like RAID 0, now with multiple platters it writes across all platters in the same way. This is where the internal RAID ends. Doing a RAID 1 might work but so far to date I have not heard of any company doing this or wanting to.

[hojnikb]

Its pretty pointless (otherwise it would be done by now) since alot of times thing go bad in a sense, that duplicate platters dont help you, as its still just one harddrive. And doing something like this would be overly expensive and for someone that actually needs this, buying two identical drives and setting up raid0 "externally" is better.

 

Now, the obvious first reaction to this is "What's the point?" Valid concern. But the way I see it, redundancy RAIDs (1, 5, 6, etc.) are there incase specific sectors on specific platters go bad, and typically these hard drives are going to be in the same system. So if a computer falls off a desk or something, it's taking all the drives down with it anyways so this way, it at least saves space.

pretty much all modern drives already have spare sectors for things like that. With smart, they relocate sectors, that are going to go bad trasparently.