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Hi,

If this observation is correct:

If two drives (preferably of equal size are set up as a RAID 1 configuration all data is mirrored between the two drives. If an error is detected on one drive the system keeps going with data from the mirrored good sector and the error is corrected on the damaged mirrored sector. The down side is that you only have half the storage capacity of the drives.

It sounds like it would be worthwhile to keep those old hard drives from broken down machines or when a new larger drive is added to your computer and set them up in an enclosure as a RAID system.

I have two spare drives now an 80GB and a 60GB of 2001 vintage -neither drive had caused any problems when I replaced them but I decided to replace them just in case.

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Last Post by ggeoff
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That observation is somewhat misleading.

Two drives can be setup in a RAID setting for mirroring (RAID1, I believe). All data is mirrored on both drives, so it would take 2x Xgb to store Xgb. (the values are not added together).

If there is a failure of one drive, it is possible to replace that drive and rebuild the data.

Mirroring (RAID1) allows a single disk failure without interruption and the capability of rebuilding the entire array.

Striping (RAID0) takes N drives but allows for zero failure. In this arrangement, the drives' capacities are added together (Nx Xgb = N(X)). The draw back is tolerance - a single drive dies and the entire array is down with data loss.

I am unsure how RAID arrays behave when the drives are not the same capacity.

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That observation is somewhat misleading.

Two drives can be setup in a RAID setting for mirroring (RAID1, I believe). All data is mirrored on both drives, so it would take 2x Xgb to store Xgb. (the values are not added together).

If there is a failure of one drive, it is possible to replace that drive and rebuild the data.

Mirroring (RAID1) allows a single disk failure without interruption and the capability of rebuilding the entire array.

Striping (RAID0) takes N drives but allows for zero failure. In this arrangement, the drives' capacities are added together (Nx Xgb = N(X)). The draw back is tolerance - a single drive dies and the entire array is down with data loss.

I am unsure how RAID arrays behave when the drives are not the same capacity.

You seem to be mirroring my post Stylish! Anyway "that drive" does not need to be replaced. I have already stated that the drives are preferably the same size -as otherwise the capacity of the larger drive is reduced. Which would be wasteful if one drive was 60GB and the other was 120GB. But to simplify:

The proposal is that a couple of old drives can still be used with little risk if they are set up as RAID 0 as if a fault develops the software heals the error on one of the drives whilst the drives are still in use.

I am expecting someone to suggest whether that is realistic or not. And if not why not. disk enclosures aren't cheap and what manages them? Maybe an old computer can be used as extra storage -they are cheap enough. My two redundant hard drives one of 60GB and the other of 80GB are, apart from their age - circa 2001 still serviceable, so why chuck them in the recycling bin?

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... The proposal is that a couple of old drives can still be used with little risk ...

A seven year old disk drive? I would trust it to be useful for testing and for educational/training purposes. But given a choice between using old drives for my system and data and buying new ones, I would buy new ones. Of course, I'd then take the old ones apart and keep the magnets. Those little magnets are pretty darn strong!

A seven year old disk drive is likely to be approaching the end of its life. The probability of it developing read and write errors is much higher. The probability of it having problems with its electronics is much higher. Seven years of heat/cool and power on/off cycles will have taken their toll.

Find smartmontools somewhere and check the drives' status. You might be surprised at what you find.

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Like Fest3er said, if you decide not to use them, at least disassemble them for the magnets (rare earth - neodymium magnets), and the incredible strong and shiny coasters, I mean platters inside. Well worth the effort. I mean who else can say they have a set of shiny coasters with holes in em, and fridge magnets that can lift the refrigerator...LOL. ~Mav

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yeah i disasembled my dead Hitatchi/IBM Deskstar once and it had wierd glass platters. You could see why it had died, the magnetic material had actually worn off of them and turned to dust. There was a groove where the head had hit it at 7000 rpm and disintegrated lol.

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yeah i disasembled my dead Hitatchi/IBM Deskstar once and it had wierd glass platters. You could see why it had died, the magnetic material had actually worn off of them and turned to dust. There was a groove where the head had hit it at 7000 rpm and disintegrated lol.

Thats pretty cool (not that it died), I have heard of newer HDDs using glass and ceramics but I have never seen them myself (though I think I have one...A Samsung Spinpoint 750Gb). I have taken many HDDs apart and only found what I believe to be a silicon-aluminum alloy. They prove to be very rigid and strong, but reasonably lightweight; perfect material for coasters.:idea:

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This was pretty old. It was like 20-40gb in size and was an upgrade for an NT4 box (found NT4 wouldnt ket you have a C bigger than like 4gb or 8gb or something, so i upgraded to win2k) so maybe early 2000s, perhaps it was ahead of its time, which is why it died.

Best hard drives are server ones seemingly. Ive got some 2.1gb (old) hotswappable 7200rpm (mush have been blazingly fast 'back in the day') SCSI drives in a compaq server and it runs 24/7 for like the 6+ years i have had it lol (before that it ran for like up to 5 years with someone else). Only one of the three disks has died which is real impressive.

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Hi Guys

Sounds like that I could make some sculpture from them after disassembly. So I won't through them away. Strong Magnets? that's intriguing.

Geoff

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