[scrooched_moose]

Are there guidelines for how long a given type of media is considered stable?

From experience, hard drives seem safe on the order of years; I've spun drives back up from the early 2000s and they are fully intact. The lifespan of burned optical media is/was counted in minutes. Various flash memory is somewhere in between - I've had all kinda of cheap flash drives die.

Even with the multiple media forms they need to be refreshed at some frequency, and I don't know how often that should be.

[ComputerGuru]

We’ve come a long way since CD-R; I said this earlier but I guess it’s worth copy-and-pasting here:

> There are Blu-ray Discs specifically engineered for long-term archiving and have BER guarantees (anomalous bit read per gb of data stored per year archived or something).

Now these are obviously simulated numbers (the tech isn’t even old enough to test) but it’s a start: it means people are at least considering the right questions.

I wouldn’t write sensitive to a Blu-ray directly unless it was the kind of data where a bit-flip is not a huge deal (eg a backup of users’ profile images where there are many small files, a bit flip affects the content but doesn’t compromise the overall data, errors aren’t cascading, etc). There’s already bit error correction baked into the analog <-> digital transition layer but it’s not great - but fortunately efficient bit error correction at the file level has been a thing since before binaries on Usenet. Stick some PAR2 files on the Blu-ray or even serve your backup as a Blu-ray Disc plus a DVD-R stuffed to the brim with PAR2 data for the former (I prefer the first approach).

[gregsadetsky]

I see a lot of results on google for "data storage lifespan"

Trying to find an authorative source (loc.gov, archive.org, etc.), I found this, which is not a full answer, but gets into interesting details: "Table 2 - the relative stability of optical disc formats" [0] -- from >100 years down to ... 5-10!

[0] https://www.canada.ca/en/conservation-institute/services/con...