SSDs Not Safe Long-Term for Archives
Monica J. White (via Mac Power Users):
SSDs rely on stored electrical charge in NAND flash cells to represent data. When an SSD is powered and in regular use, it can correct many small errors with ECC, remap weak blocks, and generally keep data reliable. Leave your SSD in a drawer, though, and it can’t do any of that.
Industry sources talk about this at length. Western Digital notes that data retention diminishes as PE cycles increase. Most SSDs run checks in the background to verify which blocks are experiencing higher bit error rates, but when the SSD is powered off, that process can’t take place.
YouTuber HTWingNut runs a (very small-scale) yearly experiment that shows what can happen to SSDs when they’re used as cold storage. The latest results after two years showed that out of four cheap TLC SSDs tested, drives that were previously heavily used (way past their recommended TBW rating) showed signs of corruption after being unpowered for two years.
[…]
If you need to park data on an SSD, check on it periodically. Power it up, run a full read/verify pass, and compare checksums for your irreplaceable files.
This is easy to do if the files are stored in EagleFiler. I periodically check all my archives, though they’re stored on spinning hard drives due to the still much higher costs and lower capacities of SSDs.
Previously:
- Self-Wiping SanDisk Extreme SSDs
- Why I’m Usually Unnerved When Modern SSDs Die on Us
- Storing SSDs Without Power
- The SSD Endurance Experiment
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SSDs would need to be stored in a "warmer" that would periodically (2-3 months) do what's needed to refresh the charge in the storage cells and do housekeeping around newly bad blocks.
Is there a consensus about what the best medium is for long term storage / archiving?
I'm definitely glad I didn't rely on burned DVDs for very long.
It's probably not hard drives. After a decade of storage in my (dry, climate-controlled) basement, about 10% no longer mount. Floppies are surprisingly resilient in comparison. Maybe tapes?
@Plume
I have a bunch of magneto-optical disks with data that was first stored on them in 1997, then subsequently until about 2002. The last time I verified their contents circa 2023, everything was still readable.
@Bri @Plume I’m not sure there’s anything great for untouched long-term. I had lots of DAT tapes once, and maybe they’re still good, but the drive (SCSI) and software no longer work with my Mac. I like hard drives, but with redundant copies and periodic migration to newer drives.
I still have some floppies with old HyperCard stacks I made when I was a kid. I should try them out and see if they're still readable.
My opinion? Redundant external SSDs, rotated. (Assuming you don't think the cloud is enough. By rotated I mean every 1-2 years replaced by new.
Yes, we aren't talking untouched. But every medium has a lifetime - be it tape, floppies, HDD, CD, SSD. Tape may work, but (1) what is the cost of tape R/W hardware and (2) what about dirt? I'm only claiming that every medium has drawbacks.Stick with the latest, and deal with the issues related to it. What you can purchase for SSD storage compared to 10 years ago should basically pay for hardware upkeep for all the other alternatives. If we are talking a multi TB transfer fro a 1-2 year old SSD to a new one, you're talking what? $200 tops for the SSD and a few hours to transfer from the old one? Maybe some day they will perfect long-term storage, but probably not in my lifetime (assuming you want something other than cloud storage).
