Unpowered SSDs in Your Drawer Are Slowly Losing Data (xda-developers.com)
- Reference: 0180206897
- News link: https://hardware.slashdot.org/story/25/11/25/1511242/unpowered-ssds-in-your-drawer-are-slowly-losing-data
- Source link: https://www.xda-developers.com/your-unpowered-ssd-is-slowly-losing-your-data/
> Solid-state drives sitting unpowered in drawers or storage can lose data over time because [1]voltage gradually leaks from their NAND flash cells , and consumer-grade drives using QLC NAND retain data for about a year while TLC NAND lasts up to three years without power. More expensive MLC and SLC NAND can hold data for five and ten years respectively. The voltage loss can result in missing data or completely unusable drives.
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> Hard drives remain more resistant to power loss despite their susceptibility to bit rot. Most users relying on SSDs for primary storage in regularly powered computers face little risk since drives typically stay unpowered for only a few months at most. The concern mainly affects creative professionals and researchers who need long-term archival storage.
[1] https://www.xda-developers.com/your-unpowered-ssd-is-slowly-losing-your-data/
Not really new information... (Score:4, Informative)
That the few extra electrons sitting isolated on some "floating gate" in a Flash RAM cell have the tendency to tunnel away over extended periods of time - and more so when exposed to more than the usual background gamma radiation - has been known since the early days of Flash RAM. If you want to archive data on some medium that you can put away for decades, magneto-optical disks are your best bet. I never lost a single bit from the 128MB MO-disks I wrote in early 1990s.
But if you want to use NVMe bars as long-term storage, you'll need to setup some rack where they can be powered occasionally - and depending on their own intelligence to test-read and re-write their content, you might also need to actually re-write their content intentionally.
Re: Not really new information... (Score:2)
I put mine into a machine once a year and dd the entire disk to /dev/null. So far, so good.
Re: (Score:2)
> So far, so good.
Just wait until you accidentally dd /dev/null to the entire disk.
(Good thing that wouldn't actually work, until our AI overlords can correct "/dev/null" to "/dev/zero")
Re: (Score:2)
Is that longevity of MO-disks partly based on how they were just built differently (less dense) back then? Kind of like the analogy to how SLC SSDs store for 10 years unlike QLC lasting far less time. My constant worry nowdays is that, in the pursuit of increased density, storage of every type has become fragile and more susceptible to errors/loss, especially when you leave it unpowered over time.
Re: (Score:2)
> Is that longevity of MO-disks partly based on how they were just built differently (less dense) back then?
No, the more dense MO-disks are just as reliable. The important point is that MO-media are far enough below their Curie-temperature at usual ambient conditions that they are "magnetically hard", so even sizable magnetic fields would not damage the information on the media. This is unlike the classic magnetic media, which is relatively easy to erase with modest magnetic fields. Would be interesting to know if modern "heat assisted magnetic recording" hard drives are of similar resilience while at ambient tem
Re: (Score:1)
What's changed is that in the early days flash memory was one bit per cell. Now most consumer grade stuff is multi level, so instead of a single threshold voltage that separates a 1 from a 0, there are multiple thresholds that each represent a different binary code.
SSDs sometimes have to re-read blocks with different voltage thresholds to get good data, and make use of error correction on top.
Presumably age related degradation is worse for multi-level flash.
Re: (Score:2)
> If you want information to last, carve it in stone and bury it in the desert.
Or pay some celebrity to throw a hissy fit in public about _that_information_ being exposed, and use the Streisand effect to have the information stored, forever, in an almost uncountable number of copies.
Re: Everything dies eventually (Score:2)
Something about real men dont backup, just upload to ftp?
Re: (Score:2)
Data tapes from the 1960s are still readable if they were stored properly. Finding working 7 track drives are a different matter.
Re: (Score:1)
Paper tapes from the [1]1750s [wikipedia.org] are still readable if they were stored properly. Finding looms from that era are a different matter (but you could make a modern reproduction).
[1] https://en.wikipedia.org/w/index.php?title=Punched_tape&oldid=1310796969#History
SSDs.... in a drawer? (Score:2)
Good grief, friend, who sets your HW budget?
Re: (Score:1)
Exactly!
"The concern mainly affects creative professionals and researchers who need long-term archival storage"
Who's paying these researchers? And why would they ever think SSD is "archival" ???
Re: (Score:2)
I have a bunch of older SSDs sitting in a bin in my hardware horde...er...closet. Occasionally find a use for them but for the most part they were replaced by larger drives over time. Luckily I don't care about whatever data is on them, anything important is backed up.
Data Retention and Wear (Score:2)
There is a JDEC spec for both consumer and data center SSDs. The consumer spec requires 1 year power off retention at 0% health remaining. The data center spec is only 90 days.
As the SSD wears, the retention goes down. Years ago, a tech magazine (remember those) did a torture test on an old MLC Samsung 3D SSDs. It was healthy with no errors at well over 10X the rated endurance. Unfortunately, the data retention was measured in days. This is why it is so important to watch SMART for wear and replace dr
Just power? (Score:2)
Does powering the drive refresh every bit? Or would you want to do something to ensure everything got read?
Re: (Score:2)
The mechanisms are proprietary but generally it works as a background refresh mechanism. So probably mostly when idle but even though it likely won't do it continously as that would wear it out and even just scanning would cause constant high power usage. It would be nice to be able to monitor when a refresh starts, how far it is, resume etc.
Spare parts (Score:2)
I just hope the firmware is stored on SLC because it sure likely isn't stored on a ROM chip. I have several SSDs that have been powered off for more than a year but with no data on them. They are used spares and have no data, but I don't want them to just stop working.
Re: (Score:2)
yeah wondering if they are storing the firmware on a separate BIOS-like flash chip (retention typically 20-40-100 years) or on the actual main flash chip to avoid that cost. Even if the drive is empty and the firmware itself survives it could be that the metadata (mapping tables etc.) could be corrupted and hence won't work anyway. I'm not sure if the drive will necessarily be able to reinitialize those metadata tables after corruption (because reinitializing them also reduces hope of data recovery). But AF
I bought a portable HDD and a SSD (Score:1)
For backing up my laptop. When I tried to use then the HDD was blank and the SSD didn't work.
How ironic...