Ask HN: Long term local physical backup media?

CDrs still are a thing, and may work "about as well".

The only surefire way for long term archival storage for the average user is to use multiple methods, and check them from time to time.

It's all a matter of cost vs how much you want to archive. If it's in the "CDr size" you can just make tons of copies, some will probably survive.

But you can also just keep that much around on every device you own and checksum it regularly.

Tape is pretty good, but even there you'd want multiple copies on different media. You could rent a drive or buy a used one, write out your tapes, and then sell the drive again.

Hard drives sitting unpowered have a "decent" change of firing back up after 10+ years, if you have the connector (externals are probably easiest) - but even there I'd want multiple copies from different vendors.

Crystals

BD-R writable DVDs seem to provide either 25GB (single layer) or 50GB (double layer) storage, and seem like they would have longer lifetime than spinning discs, SSDs, or tape. I guess if I can deal with 50GB chunks that may be the best option.

You could use M-DISCs, which look like traditional CDs nut are made for long-term storage and should be readable much longer than other CDs, DVDs and Blu-rays. The optical drives for burning M-DISCs are readily available and not very expensive.

If you're only looking to store a small amount of data then writable discs (CD, DVD, etc) are still easily available. Just make sure to keep them out of direct sunlight as that can affect their long-term readability.

If you need to store a larger volume of data then you'll probably be looking at tape of some form of hard disk/SSD.

Either way you can reduce the risk of loss by having a regular process of copying the old data to new media and keeping both the old and new media - that way if one copy of your data fails you'll still have other copies that you can use.

My current thinking.

CD's are the equivalent of CD's. Like you said, thirty years later they still work.

DVD's are probably close.

Spinning disks are probably ok if used as write once.

All of these have lots of compatible hardware and software.

Tape is great at scale. But you're not at scale.

The cloud is one declined credit card away from erasure.

Good luck.

It looks like a RAID setup might remove your concern for moving parts, while benefiting from a cheaper storage price.

I had this concern myself and eventually I gave up and do it on cloud.

m.2 SSD with redundancy treatment e.g. par2, should get the job done and happier to work with, because r/w rate is the highest among all options.