Comment by shiroiushi

Comment by shiroiushi 10 days ago

2 replies

Somehow it seems ironic that a forum dedicated to understanding the long-term viability of data storage, an important topic lately because of the unreliability of 3rd-party providers (like cloud companies), itself became a victim of the unreliability of its own webmaster.

128GB BD-R discs do exist, but at $219 on Amazon for 25 discs, that's about $0.07/GB. It would be MUCH cheaper to just buy a stack of refurbished enterprise-class HDDs and store your data on those, in triplicate, with a filesystem that has error correction (like ZFS). Personally, I would bet on HDDs used this way still being readable and not having bit-rot after 50 years over 4-layer BD-R discs.

Springtime 10 days ago

Wouldn't it be more like $0.07/GB for BDXL? If one got particularly lucky with HDD failure rates perhaps they'd survive running that long in RAID but one would expect some replacements over such a long period.

Some other things to consider are at high capacities all HDDs use helium now, which slowly leaks (WD/HGST have a SMART stat about the level*) and the cost of running drives/associated computers/maintenance over a long span vs the up front cost of passive writable media (edit: for some reason I assumed this was what was meant but they could be left cold which would likely increase survival odds and be cheaper).

* And there isn't much long term data about it that I could find, though some have reported between 1-5 years the SMART stat either remaining at max or dropping a few digits. Even Backblaze outside of their first article a year into using them hasn't seemingly continued reporting on the stat that I've noticed. I get the sense though that other types of failures are expected sooner than leaks.

  • shiroiushi 10 days ago

    >Wouldn't it be more like $0.07/GB for BDXL?

    Whoops, thanks for pointing out the math error; I've fixed it.

    >If one got particularly lucky with HDD failure rates perhaps they'd survive running that long in RAID but one would expect some replacements over such a long period.

    I don't think so: I'm not talking about keeping these drives spinning for 50 years, but rather in cold storage, just as we'd do with the BDXL discs.

    >Some other things to consider are at high capacities all HDDs use helium now, which slowly leaks (WD/HGST have a SMART stat about the level*) and the cost of running drives/associated computers/maintenance over a long span vs the up front cost of passive writable media.

    Helium leakage is an issue I didn't think of, and I don't know how sitting in cold storage for 50 years would affect this. But again, the costs of running drives/maintenance/etc. should be zero, because I'm comparing apples to apples. No one would seriously propose a massive array of BDXL drives with BDXL discs continuously available, so likewise I'm proposing just keeping 10+TB HDDs in cold storage.