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Comment by Eisenstein | Hacker News Reader

Something useful to know that wasn't mentioned: SSDs will corrupt data if sitting for extended periods without being powered on and thus should never be used for cold storage.

"There are considerations which should be made if you are planning on shutting down an SSD based system for an extended period. The JEDEC spec for Enterprise SSD drives requires that the drives retain data for a minimum of 3 months at 40C. This means that after 3 months of a system being powered off in an environment that is at 40C or less, there is a potential of data loss and/or drive failures. This power off time limitation is due to the physical characteristics of Flash SSD media's gradual loss of electrical charge over an extended power down period. There is a potential for data loss and/or flash cell characteristic shift, leading to drive failure."

* https://www.ibm.com/support/pages/potential-ssd-data-loss-af...

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Relevant: Nintendo 3DS and Switch game carts go bad unless played https://news.ycombinator.com/item?id=39367506

Note that retention increases exponentially with decreasing temperature, so literally "cold storage" might actually be OK for SSDs.

The retention also goes down with erase cycles, and is usually specified after the rated number of cycles have been reached; I expect those same SSDs to hold their data much longer than 3 months if they're still nearly new.

I still have USB drives over a decade old, but their contents are still intact. Then again, those haven't been written to much, and are SLC and older 2-bit MLC.

Those are drives that weren't plugged in for a decade? How do you know the contents are intact?

Probably by plugging it in and eyeballing all the contents. I have a similar experience with 1GB ancient USB drive.

Did you literally never plug the drive in for over a decade or so, not once? Then you checked the contents for corruption and it was clean?

I ran into this for the first time a couple weeks ago. I tried to boot a system from an SSD that had sat for about 9 months at normal room temperature w/out power. It stumbled badly, repeatedly. I booted a live USB, ran non-destructive `badblocks` scan on it and reinstalled the OS. It's been working fine since.

I thought SSDs would last longer than 9 months w/out losing data when not powered.

> Something useful to know that wasn't mentioned: SSDs will corrupt data if sitting for extended periods without being powered on and thus should never be used for cold storage.

I've got burnt by this the hard way. Even in the early 2000s, HDDs from the mid-90s were often still bootable after years of sitting in still contemplation. No such longevity for SSDs.

Makes me wonder if those external SSD drives made by Samsung and WD/Sandisk take that into account and use different flash memory with better longevity without power.

Unlikely in the case of Sandisk, which is known for a recent bout of extremely unreliable external SSDs: https://arstechnica.com/gadgets/2023/08/sandisk-extreme-ssds...

If anything, I would expect consumer SSDs to use the cheapest/lowest grade of flash available.

Small USB flash drives get the worst NAND, followed by memory cards, then consumer SSDs, then enterprise SSDs. "Portable SSDs" that are physically much larger than USB thumb drives usually contain standard consumer SSDs in mSATA or M.2 form factor, plus a bridge chip.

I assume this is the same for all NAND? i.e Flash / SD Card and USB Drives ?

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