Digital storage

Started Oct 14, 2012 | Questions thread
kelpdiver
Senior MemberPosts: 1,935
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Re: Digital storage
In reply to apaflo, Oct 17, 2012

apaflo wrote:

Actually there are no such things as USB drives.  In fact what they all have is one of two different things, it is either an IDE drive with an IDE to USB converter or it is a SATA drive with a SATA to USB converter.  Which is to say that if the USB interface actually did disappear, the solution is simply to take the device apart and plug the drive into something that matches is native interface.  Neither IDE nor SATA is going to disappear any time soon, but eventually they will be almost as difficult to find aS are 8 inch floppy drives today.  That is, not very hard if you know where to look but not something everyone realizes.

I was thinking really about USB flash drives, not hard drives with a USB interface.  Samsung sells a Media Vault product with a claimed 100 years life.   So you do need the USB interface for these.  But thinking about that more - you can still buy a db9 serial port for your PC.  It's long been unusual to see it on the motherboard by default, but often the pinouts are still there.  So even when USB goes by the wayside, it's likely to be easily added for many decades to come.

Bit rot is the primary threat now.  For the slick unix types, zfs solves this.  For windoze users, ReFS will soon be released.

I had never looked at zfs before, and your comment caused me to do a google search and find out what it was you meant by that!  Thank you, because that bears some further looking into.

It was very telling when I first started using it, including for a single drive serving up movies.  I started seeing bit rot on files I was accessing.  This wasn't essential data, and it probably isn't surprising to hear that the drive failed outright 2 years later, but it points to the unreliability of a single drive.  Not all drives fail completely and obviously.  And then when you look at the stated error rates for normal operation (1 in 10^14) and compare to our data set sizes now, they're not that far apart.  The risk here is that if people keep copying data from one generation of storage to the next, these errors may accumulate silently.

I now use zfs mirroring and thus have two copies of every image.  If some bits get corrupted, scrubbing should identify and repair.  If it outright failed, I could then go to backups immediately.  For single drive use, there is an option to store 2 (or X) copies of each file for the same purpose.  None of this protects against human error - they don't replace backups.  They only address media faults.

Microsoft seems to have copied the feature set for zfs for their refs work.  It is due to show up initially in their Server product for Win8, but I would expect it to trickle down to the desktop side in the year or two after...ntfs is way past its day.

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