Is bit rot a concern?

[silicon]

I have about 3 TB of data with one back-up copy. The file system used is NTFS.

Anyways, I was wondering about bit rot recently, if I should be concerned, and possible ways to protect against it (without building a ZFS machine).

Please explain what bit rot is. First time hearing this.

 

[Cerb]

Please explain what bit rot is. First time hearing this.

It's one class of UREs (unrecoverable read errors). If you write your data, then read it back right then to verify, and all is fine, but then reading back the same data fails after it's been sitting for some time, that's bit rot.

A good write to a good platter surface should last quite a long time--maybe decades--before it's a concern. However, writes that are just barely readable by ECC, not well-centered or otherwise well-aligned on the track, written to weak sectors (sectors that are usable enough to keep from being marked bad, but just barely), or from some other scenarios I'm not aware of, may not be so lucky. Many, if not most, HDDs, could go their entire usable lives without encountering a single such problem. But, having seen it myself, it can and does happen.

On the plus side, generally good backup/recovery methods for generalized UREs will also cover bit rot, should you encounter it, so it's not worth worrying overly much about, as specific class of failures. Archives with checksums, and file systems with checkums, can detect it, and much more common data loss/corruption cases, equally well.

Optical writable media suffers from bit rot as a failure mode almost exclusively, assuming decent media.

 

[corkyg]

It really goes back to the mid 1980s and the days of 5.25-in and 3.5-in floppies. Bit rot was simply a jargon referring to the natural decay of magnetic oxide on that media. HDDs had not yet bubbled up except for the old HardCard. Don't try and over tech the term - it is simply engineer slang used to explain deterioration of such media due to poor storage (temp and humidity) - it was really not a common thing, but did occasionally happen.

 

[Phynaz]

It really became a problem with recordable CD media deterioration.

 

[corkyg]

It really became a problem with recordable CD media deterioration.

True. Recordable opticals use a varnish layer, and that would often react poorly to applied paper labels adhesives. But, technically speaking, while it was a decay or degredation of the recording, it was not really bit rot as loosely defined by the originators of the term.

 

[Cerb]

True. Recordable opticals use a varnish layer, and that would often react poorly to applied paper labels adhesives.

Not since the 90s (IE, they fixed that with DVD). The data deteriorates anyway, on most discs.