Unpowered SSDs slowly lose data • Hacker News Board

Re: Unpowered SSDs slowly lose data

#251

Post by Aurornis » Tue, Nov 25, 2025, 2:35 PM UTC

ACCount37 wrote: post #182

userbinator wrote: post #168

Earlier quoted context omitted.

4 times less capacity but 100x or more endurance or retention at the same price looks like a great deal to me. Alternatively: do you want to have 4x more capacity at 1/100th the reliability? Plenty of people would be willing to pay for SLC mode. There is an unofficial firmware hack that enables it: https://news.ycombinator.com/item?id=40405578 1TB QLC SSDs are But why won't the manufacturers let you choose? The real…

The real answer is: no one actually cares. Very few people have the technical understanding required to make such a choice. And of those, fewer people still would actually pick SLC over QLC. At the same time: a lot of people would, if facing a choice between a $50 1TB SSD and a $40 1TB SSD, pick the latter. So there's a big incentive to optimize on cost, and not a lot of incentive to optimize on anything else. This "…

> Very few people have the technical understanding required to make such a choice. And of those, fewer people still would actually pick SLC over QLC.

There was a period of time when you could still by consumer SLC drives and pay a premium for them. I still have one.

Anyone assuming the manufacturers are missing out on a golden market opportunity of hidden SLC drive demand is missing the fact that they already offered these. They know how well (or rather, how poorly) they sell.

Even if consumers had full technical knowledge to make decisions, most would pick the TLC and QLC anyway. Some of these comments are talking about optimizing 20 year old drives for being used again two decades later, but ignoring the fact that a 20 year old drive is nearly useless and could be replaced by a superior option for $20 on eBay.

The only thing that would change, practically speaking, is that people looking for really old files on drives they haven’t powered up for 20 years wouldn’t be surprised that the were missing.

The rest of us will do just fine with our TLC drives and actual backups to backup services or backup mediums.

I’ll happily upgrade my SSD every 4-5 years and enjoy the extra capacity over SLC while still coming out money ahead and not losing data.

Re: Unpowered SSDs slowly lose data

#252

Post by Aurornis » Tue, Nov 25, 2025, 2:38 PM UTC

bullen wrote: post #154

RachelF wrote: post #83

Earlier quoted context omitted.

Endurance going down is hardly a surprise given that the feature size has gone down too. The same goes for logic and DRAM memory. I suspect that 2035 years time, hardware from 2010 will work, while that from 2020 will be less reliable.

I concur; in my experience ALL my 24/7 drives from 2009-2013 still work today and ALL my 2014+ are dead, started dying after 5 years, last one died 9 years later. Around 10 drives in each group. All older drives are below 100GB (SLC) all never are above 200GB (MLC). I reverted back to older drives for all my machines in 2021 after scoring 30x unused X25-E on ebay. The only MLC I use today are Samsungs best industrial…

> in my experience ALL my 24/7 drives from 2009-2013 still work today and ALL my 2014+ are dead,

As a counter anecdote, I have a lot of SSDs from the late 2010s that are still going strong, but I lost some early SSD drives to mysterious and unexpected failures (not near the wear-out level).

Re: Unpowered SSDs slowly lose data

#253

Post by Aurornis » Tue, Nov 25, 2025, 2:39 PM UTC

cesaref wrote: post #227

pbmonster wrote: post #133

Earlier quoted context omitted.

I know we're talking theoretical optimums here, but: don't put your SSDs in the freezer. Water ingress because of condensation will kill your data much quicker than NAND bit rot at room temperature.

I'm interested in why SSDs would struggle with condensation. What aspect of the design is prone to issues? I routinely repair old computer boards, replace leaky capacitors, that sort of thing, and have cleaned boards with IPA and rinsed in tap water without any issues to anything for many years.

Condensation == water. Water leads to corrosion.

Re: Unpowered SSDs slowly lose data

#254

Post by Aurornis » Tue, Nov 25, 2025, 2:40 PM UTC

dachris wrote: post #151

pbmonster wrote: post #133

Earlier quoted context omitted.

I know we're talking theoretical optimums here, but: don't put your SSDs in the freezer. Water ingress because of condensation will kill your data much quicker than NAND bit rot at room temperature.

Would an airtight container and liberal addition of dessicants help?

Be careful, airtight doesn’t mean it’s not moisture permeable over time.

Color changing desiccant is a good idea to monitor it.

Re: Unpowered SSDs slowly lose data

#255

Post by lazide » Tue, Nov 25, 2025, 3:14 PM UTC

jeremyvisser wrote: post #218

lazide wrote: post #213

Earlier quoted context omitted.

Huh? The issue being discussed is random blocks, yes? If your entire drive is bricked, that is an entirely different issue.

Here’s the thing. That SSD controller is the interface between you and those blocks. If it decides, by some arbitrary measurement, as defined by some logic within its black box firmware, that it should stop returning all blocks, then it will do so, and you have almost no recourse. This is a very common failure mode of SSDs. As a consequence of some failed blocks (likely exceeding a number of failed blocks, or perhaps…

Yes, and? HDD controllers dying and head crashes are a thing too.

At least in the ‘bricked’ case it’s a trivial RMA - corrupt blocks tend to be a harder fight. And since ‘bricked’ is such a trivial RMA, manufacturers have more of an incentive to fix it or go broke, or avoid it in the first place.

This is why backups are important now; and always have been.

Re: Unpowered SSDs slowly lose data

#256

Post by pluralmonad » Tue, Nov 25, 2025, 3:33 PM UTC

justin66 wrote: post #64

pluralmonad wrote: post #5

Earlier quoted context omitted.

I learned this when both my old laptops would no longer boot after extended off power time (couple years). They were both stored in a working state and later both had SSDs that were totally dead.

Were the SSDs toasted, or were you able to reinstall to them?

D.E.A.D.

Had to replace them.

Re: Unpowered SSDs slowly lose data

#257

Post by deltoidmaximus » Tue, Nov 25, 2025, 3:35 PM UTC

leo_e wrote: post #234

We learned this the hard way with "cold" backups stored in a literal safe. We treated NVMe drives like digital stone tablets. A year later, we tried to restore a critical snapshot and checksums failed everywhere. We now have a policy to power-cycle our cold storage drives every 6 months just to refresh the charge traps. It's terrifying how ephemeral "permanent" storage actually is. Tape is annoying to manage, but at…

What does power-cycle mean in this case?

I've seen this topic come up a lot on a datahoarder forum but there was never any consensus on what it would take to assure the data was refreshed because no one really knew how it worked. People would assume anything from a short power up to simply rewriting all data as possibilities.

The firmware engineer responding up thread is actually the best information I've seen on this. And it kind of confirmed my suspicions. He works on enterprise drives and they run a refresh cycle as background cycle that seems to start on a random timer. I didn't see any response (yet) on how long this process takes but I think we can infer that it takes a while based on it being a background process. Probably hours or more. And this is all for an enterprise drive, I wouldn't be surprised if consumer drives have a less robust or even non-existent refresh function.

I'm of the opinion that that based on the little information about some implementations of this function, the logical conclusion is you should just rewrite all of the data over again on your cold backups for the cycle. Powering it on isn't enough, even powering it on for a day might not do anything. As you said this is a pretty big drawback for uses flash as a cold backup.

Re: Unpowered SSDs slowly lose data

#258

Post by lizknope » Tue, Nov 25, 2025, 3:37 PM UTC

I've been hearing about this for years and it makes sense theoretically but has anyone ever actually seen it? What are the errors reported? Or does the drive return bad data but reports no error?

There was a guy on reddit that took about 20 cheap USB flash drives and checked 1 every 6 months. I think after 3 years nothing was bad yet.

I've copied OS ISO images to USB flash drives and I know they sat for at least 2 years unused. Then I used it to install the OS and it worked perfectly fine with no errors reported.

I still have 3 copies of all data and 1 of those copies is offsite but this scare about SSDs losing data is something that I've never actually seen.

Re: Unpowered SSDs slowly lose data

#259

Post by deltoidmaximus » Tue, Nov 25, 2025, 3:47 PM UTC

mbreese wrote: post #205

dotancohen wrote: post #185

Earlier quoted context omitted.

In threads like this I keep hearing about ZFS. What would be the drawbacks of running ZFS as a home user? I keep my OS on the SSD and my files on spinning rust, if that's relevant.

1) you have to have an OS that supports it. 2) even if your OS supports it, you may have difficulty using it for your root volume, so partitioning is probably required. 2a) in your case you may not want to use it on your boot volume which would negate the SSD benefit for you. 3) it is recommended that you have ECC RAM due to the checksums. This isn’t a hard and fast requirement, but it does make you more resilient to…

I'm always surprised how often ZFS is recommended when this comes up but not BTRFS which also has checksumming and scrubs and doesn't suffer some of ZFS's drawbacks of complexity and OS integration.

Re: Unpowered SSDs slowly lose data

#260

Post by tensility » Tue, Nov 25, 2025, 3:53 PM UTC

RachelF wrote: post #83

userbinator wrote: post #77

One key point about retention which is not often mentioned, and indeed neither does this article, is that retention is inversely proportional to program/erase cycles and decreases exponentially with increasing temperature. Hence why retention specs are usually X amount of time after Y cycles at Z temperature. Even a QLC SSD that has only been written to once, and kept in a freezer at -40, may hold data for several de…

Endurance going down is hardly a surprise given that the feature size has gone down too. The same goes for logic and DRAM memory. I suspect that 2035 years time, hardware from 2010 will work, while that from 2020 will be less reliable.

Oh, it would be nice if it were just feature size. Over the prior 15 years, the nand industry has doubled its logical density three times over with the trick of encoding more than one bit per physical voltage well, making the error bounds on leaking wells tighter and tighter and amplifying the bit rot impact, in number of ECC corrections consumed, per leaked voltage well.