[HN Gopher] Flash media longevity testing - 6 years later
___________________________________________________________________
Flash media longevity testing - 6 years later
Author : 1970-01-01
Score : 117 points
Date : 2026-03-08 16:22 UTC (1 days ago)
(HTM) web link (old.reddit.com)
(TXT) w3m dump (old.reddit.com)
| jmakov wrote:
| Powered all the time on or powered off?
| alnwlsn wrote:
| OP says powered off.
| monster_truck wrote:
| Rewriting the data each year hides the actual issue here. Have
| had plenty of "nice" flash drives rot to hell in 18+ months of
| dormancy
| benterris wrote:
| Does rewriting data help prevent bit rot? Does it mean powered
| drives can take advantage of it by periodically rewriting the
| same data over?
| vel0city wrote:
| It depends on how the flash modules are maintained and their
| quality, but yes having freshly written data will imply
| better data consistency on flash media.
|
| Flash media relies on recharging, which may or many not
| happen often enough.
| monster_truck wrote:
| It depends on the type of flash being used and the controller
| managing it. That he did not even identify the chips should
| inform you of the extent that these results can be trusted.
|
| All I can say for sure is that you should not trust any flash
| for long term storage, thumb drive or otherwise. In serious
| enough, high usage, high heat enviornments where everything
| working without problems or delay is part of what they are
| paying us to be responsible for, it is standard practice to
| clone fresh images to nvmes every time, with multiple spares
| that can be swapped out in minutes when they inevitably fail
| anyways.
| angry_albatross wrote:
| Did you miss that there are 10 different drives and so they
| have 10 different years of tests where they are testing a
| completely untouched drive?
| monster_truck wrote:
| I don't think you're reading the results properly.
| thinkling wrote:
| I think they are reading it correctly. Year 1, they touched
| one drive and left 9 untouched. Year 2, they read one
| additional drive and left 8 untouched. Etc.
| monster_truck wrote:
| Those drives aren't being read
| Springtime wrote:
| Yes, it's also confirmed on the OP's blog linked in the
| post.
| angry_albatross wrote:
| What do you think I am I reading incorrectly? The post
| seems pretty clear:
|
| "I filled 10 32-GB Kingston flash drives with pseudo-random
| data."
|
| "The years where I'll first touch a new drive (assuming no
| errors) are: 1, 2, 3, 4, 6, 8, 11, 15, 20, 27"
|
| And from the blog: "Q: You know you powered the drive by
| reading it, right? A: Yes, that's why I wrote 10 drives to
| begin with. We want to see how something works if left
| unpowered for 1 year, 2 years, etc."
| ComputerGuru wrote:
| Slightly related: I have a tool that writes random
| (incompressible) data to a disk and lets you verify it back
| without storing a copy (by using a csprng seed), initially
| developed for benchmarking SSDs that used to cheat to get better
| performance numbers but that can also be used for this purpose or
| to overwrite ("shred") a disk: https://github.com/mqudsi/hddrand
| fhdkweig wrote:
| I haven't used badblocks
| https://en.wikipedia.org/wiki/Badblocks in about 10 years, but
| I was annoyed that this exact feature wasn't available for
| testing accidental swapping of block locations. badblocks only
| writes the same data to each block and thus they are all
| indistinguishable.
| champtar wrote:
| TIL `badblocks -t random` repeats the same random block over
| and over :(
| jmb99 wrote:
| You can however set the block size to something quite
| large, which means you write the same random pattern
| _spread out over multiple blocks_ repeatedly. If you pick
| an "odd" block size (like say, your native block size
| multiplied by 47), it's highly unlikely your disk under
| test will be swapping around "groups of 47 blocks." (I
| usually just do a nice multiple, like 4K _16, but if you
| 're super paranoid a weird multiple should be pretty much
| good enough). You won't get reporting of which _exact*
| blocks on the drive are failing, but these days, that isn't
| really useful information - if any blocks are failing,
| warranty or ditch the drive.
| 01HNNWZ0MV43FF wrote:
| That's good. I want to keep some institutional knowledge and
| photos in "cold storage" and cloud subscriptions with a credit
| card and password are completely inviable.
|
| I'll probably get a spinner and a flash drive and hope one of
| them survives the years.
| fhdkweig wrote:
| If privacy is your primary problem with cloud storage, I would
| suggest veracrypt containers. And if you aren't storing too
| much data, I would also suggest DVD/BluRay optical media with
| DVDisaster and PAR2 archives. I keep a DVD spindle in a safe
| deposit box that gets updated each year.
| rpcope1 wrote:
| Unless the data is huge, you're probably going to be better off
| with M-Disc Blurays or DVDs, as they're explicitly designed for
| what you're trying to do.
| nullorempty wrote:
| What's the simplest way to rewrite the data without actually
| copying the data? Like in place rewrite - you write what you
| read.
| fhdkweig wrote:
| I've seen "dd if=/dev/removable of=/dev/removable" suggested. I
| don't know if it actually works or if the OS optimizes it to a
| no-op.
| piyh wrote:
| the risk of catastrophic data loss from misuse of `dd` makes
| my hackles rise just looking at this.
|
| I will never forget when I mixed up `if` and `of` during a
| routine backup.
|
| `cat /dev/sda > /mnt/myDisk2` is so much safer, explicit, and
| in unix norms. It's also faster because you don't have to
| tune block size parameters.
|
| Plus you can also do `pv /dev/sda > /mnt/myDisk2` to get
| transfer speed details.
|
| Friends don't let friends use `dd` where `cat` can do the
| same job.
| jmb99 wrote:
| I stopped getting scared of `if` and `of` about a decade
| ago when I started explicitly saying (in my head) "input
| file" and "output file" rather than "if" and "of." You
| still can mess up the order, but imo no more easily than
| you can swap `cat in > out` for `cat out > in`.
|
| > Friends don't let friends use `dd` where `cat` can do the
| same job.
|
| Technically yes... but I like being able to explicitly set
| block sizes and force sync writes.
| valleyer wrote:
| Certainly the OS can't optimize it to a no-op, since `dd`
| makes separate read and write syscalls.
|
| I suppose your `dd` implementation _itself_ could do so, but
| I don 't know why it would.
| hpb42 wrote:
| Wouldn't a ZFS Scrub get the job done?
| ralferoo wrote:
| I like the fact he's not just verifying all of them each year.
| AFAICR, reading the flash causes the row to be rewritten with the
| values just read.
|
| I remember years ago working on the Wii, and there was a
| restriction on how often you could read the flash to avoid
| premature wearing. Not sure if that was just the specific type of
| storage, as googling suggests that NAND is subject to this and
| NOR isn't. I think pretty much all USB drives now use NOR flash,
| so maybe this isn't actually an issue any more.
| wmf wrote:
| _reading the flash causes the row to be rewritten with the
| values just read_
|
| DRAM works that way but flash doesn't. Read disturb is a
| different issue.
|
| _pretty much all USB drives now use NOR flash_
|
| Nope, NOR flash is much more expensive than NAND so NOR is only
| used for firmware and everything else is NAND.
| cyberax wrote:
| But the firmware might have the logic to rewrite the block
| when it reads it in case it hasn't been written in a while.
| wmf wrote:
| SSDs should definitely rewrite static data if it has too
| many ECC errors. Unfortunately we don't know much about
| what's going on in SSDs. Some could have much better data
| integrity than others.
| zozbot234 wrote:
| > reading the flash causes the row to be rewritten
|
| This only happens very rarely, though more frequently as NAND
| flash goes QLC and beyond.
|
| Besides, other experiments have shown that data remanence is
| way more of an issue with drives that are almost completely
| worn out (way beyond their specified TBW) and about to croak.
| Even then you only get rare bitrot that can be checked for and
| compensated quite cheaply in most cases.
|
| If you take fresh media, write it just once or a few times at
| most, use substantial overprovisioning to keep the drive in its
| fast pseudo-SLC mode, and reread the media periodically, NAND
| can be a good enough storage system for most casual needs.
| digdugdirk wrote:
| What is the best consumer friendly long-term storage medium? Are
| we still better off with high capacity dvd/Blu ray discs?
| 1970-01-01 wrote:
| I've been a big fan of M-Disc BD-R.
| BoredPositron wrote:
| What's long-term? I have some dvd-rs that push 20-25 years and
| despite the plastic getting brittle they still work. I also
| have some ide drives that still work without problems after 40
| years. I would rather aim for 20 years and upgrade the storage
| device if I still need to retain the data.
| vel0city wrote:
| That's a thought I hadn't had. The plastic of the disk
| getting so brittle it shatters in the drive due to age. I
| wonder what's the embrittlement profile of polycarbonate
| stored in reasonable condition.
| mrob wrote:
| I've personally never noticed brittleness in old optical
| discs (unlike the polystyrene jewel cases, which often turn
| brittle). I don't think shattering is likely, but if it's a
| concern some optical drives allow limiting the maximum spin
| speed. If the drive supports it you can temporarily set it
| with the -x option of the "eject" command from util-linux.
| orthogonal_cube wrote:
| Probably depends on what "consumer-friendly" entails, how it's
| stored, and the quantity of data.
|
| If we're talking the average tech-illiterate to literate-but-
| cost-and-space-constrained person, probably Blu-Ray. A
| burner+reader combo with a stack of dual-layer discs is
| probably cost-effective. High-capacity HDDs would probably be
| equally effective _if_ you can guarantee that they're stored
| away from accidents and mishandling, but if it requires a SATA-
| to-USB adapter with assembly then it might possibly be out of
| reach for some consumers, and any risk of damage from movement
| could rule it out entirely.
|
| If we're talking tech-savvy consumers who don't have the IT
| budget of a corporation, maybe LTO-5 or LTO-6 tapes could work.
| Tapes themselves are very affordable and have a good shelf
| lifespan. Used libraries can be had for under $600. The primary
| issues would be finding one with an interface that works with
| your existing equipment and software to support tape read and
| write.
| layer8 wrote:
| Honestly: multiple copies of encrypted cloud storage.
| (Encryption just for privacy.) You need decentralized backups
| anyway. Alternatively, two NAS systems with some RAID variation
| in different locations that back up each other can be more
| cost-effective for large capacities.
| foxglacier wrote:
| You're talking about backups which you wouldn't normally need
| to keep for decades and will be powered on regularly anyway.
| If it's archival, such as family photos for your kids when
| they grow up, cloud storage can lose them if you die or go to
| prison or for whatever reason don't keep paying the bill.
| bityard wrote:
| Recordable blu-ray discs have a reported lifespan of hundreds
| of years if left untouched, but the high-capacity ones (128GB)
| are not especially cheap right now and I assume the writing
| process is slow. The drives themselves may not be easy to come
| by in future decades. But they are your best bet for "I want my
| data to outlive my grandchildren."
|
| For the rest of us, a USB spinning rust hard drive formatted as
| exFAT is going to be hard to beat. You'll be able to plug this
| into virtually any computer made in the next few decades
| (modulo a USB adapter or two) and just read it. They are cheap
| (even allowing for the rising cost of storage), fast, and most
| importantly, they are easy. The data is stored magnetically, so
| is not susceptible to degradation just from sitting like SSDs
| or flash drives are.
|
| Of course, you should not store any important data on only ONE
| drive. The 3-2-1 backup rule applies to archives as well: 3
| copies, 2 different media, 1 off-site.
| fy20 wrote:
| I decided to go with NTFS for the filesystem as it has
| journaling. Works fine on Linux, and obviously Windows. For
| macOS there are various add-ons that support NTFS, but my use
| case there is read-only.
| msy wrote:
| Consumer? Apple or Google Photos or 'drive' functionality of
| either. The only real risk then is losing your account and
| Apple Photos has an option to keep them all locally on disk.
| curt15 wrote:
| To be pedantic, the post you responded to asked about
| "storage medium", not storage services, which leads to the
| question of what storage medium they use and how long the
| services will be around.
| somat wrote:
| On a related subject, physical media, like a song album. I
| started by wondering if there were ever any solid state
| distribution options (One Company tried SD cards) and then
| started digging into the underlying storage tech to see if I
| could find a write once long term stable process.
|
| First the elephant in the room. Why solid state? because the
| drives to read the media are often the weak link. When the drives
| are no longer being manufactured how hard is it to make one?
| reading solid state drives is a relatively low precision
| electrical process compared to the high precision mechanical
| process needed for most media.
|
| First on the chopping block was bulk storage. It tends to be
| delicate and hard to read and short lifespans. But if I limited
| myself to small storage there are some interesting options.
| fusible proms were promising but top out at a few megabytes. Mask
| roms? does anyone offer a mask rom service anymore?
|
| Put a mask rom into a sd card... no, sd cards are too physically
| small. For a song album we want something bigger to put album art
| on. A thing the size of the original gameboy cartridge with a usb
| interface and a mask rom?
|
| My conclusion, for that specific goal, indefinite future storage
| of a song album. Vinyl records. low tech enough that it is easy
| to make a player for them.
| deltoidmaximus wrote:
| Interesting related thread that includes SSD firmware engineer
| fairfeather discussing refresh mechanism implementation:
| https://news.ycombinator.com/item?id=46038099
| rambambram wrote:
| I could google it, but I would rather ask HN: what are the best
| pens (or pen(cil)/paper-combination) for keeping written text as
| long as possible? I had some Stabilo pen which was very nice
| ergonomically, but the blue ink faded within a couple of years
| (laying on my window sil in the sun, but still).
|
| My guess is: regular graphite pencil on porous paper is best. Any
| ideas about further things I have to take into account?
| sandworm101 wrote:
| Black ink on white paper, stored in a cool dark place, will
| last many decades. If may fade but will remain readable. Want
| centuries? Use skin parchment. Millenia? An engraving pen on
| glass. Going for longer? Take a grinder to a block of granite,
| but the real problem there is the lack of geologically-stable
| storage on this planet.
| nine_k wrote:
| Granite is heavy and brittle. Instead, take a plate made of
| platinum or iridium, and engrave information on it. It offers
| excellent mechanical, chemical, and thermal durability. It
| can sink in volcanic lava and then hammered back out from the
| resulting rock, intact. (Expensive though.)
| rambambram wrote:
| A couple of millennia might suffice. ;) Thanks for the input.
|
| The engraving pen on glass is a good one. Any experience with
| it?
| ian-g wrote:
| An engraving pen on glass? Why not get some sheet glass and a
| stick of color. Write it directly onto the glass _in glass_
| fhdkweig wrote:
| I vote for graphite on paper. Ink will run if the paper gets
| wet. Of all the damage that has occurred to my papers, water is
| the most common. I keep a copy of important phone numbers
| written inside my wallet in case I ever lose my phone. Between
| an unexpected rainstorm, to an unchecked pocket before putting
| pants in a washing machine, to a spilled drink, I have gotten
| my wallet wet several times. Every time I used ink, I had to
| rewrite the list, but now with graphite, it isn't a problem.
| rambambram wrote:
| Thanks! I appreciate the input.
|
| Do you just use regular graphite pencils, like with the HB
| scale or something?
| fhdkweig wrote:
| I just use the same BIC mechanical pencils with #2 lead
| that I picked up in college. No reason to get complicated.
| lich_king wrote:
| I don't think there's a simple answer. For example, someone
| recommended black ink on white paper, but it really depends on
| the composition of that ink. Inorganic pigments last forever,
| but the ink used in black sharpies actually fades pretty
| quickly.
|
| Pencil definitely lasts if the paper is undisturbed. I have
| some paperwork that's 100+ years old and with legible pencil
| text. On the flip side, if the paper is handled a lot, the
| writing will gradually fade because graphite particles just sit
| on the surface and can flake off.
|
| On some level, the medium is your main problem. Low-grade
| paper, especially if stored in suboptimal conditions (hot
| attic, moist crawlspace, etc), may start falling apart in 20
| years or less. Thick, acid-free stock stored under controlled
| conditions can survive hundreds of years.
| rambambram wrote:
| Thanks for the insight.
|
| Acid-free paper sounds like the way to go. Do you have
| experience with this? Or is it common knowledge? Just
| curious!
|
| I also read letters from my grandparents, stored by my
| parents in a simple shoe box. No special conditions, just
| light-free and inside the home for decades. They were still
| very much readable. I did not pay enough attention, but I
| guess it was blue ink from back in the day that they used.
| lich_king wrote:
| > Do you have experience with this? Or is it common
| knowledge? Just curious!
|
| I collect vintage stuff that sometimes comes with
| paperwork, usually after spending a decade or two stashed
| away in the attic.
| wrboyce wrote:
| In the UK "registrar's ink" is used for marriage certificates,
| I believe it is supposed to be good for many hundreds of years.
| Havoc wrote:
| I'd think thin copper sheet on something soft would also work.
| That indentation will probably outlast any sort of ink
| jofla_net wrote:
| Buyer be warned i think this is extremely brand-dependent.
|
| While i've had generally solid experience with sandisk for almost
| 20 years and had a few old drives (which i hear are slc-based so
| its not surprising) hold files for over 5 years no issue, i
| recently almost lost over 4 years of photos.
|
| I had purchased some lexar drives from costco since they were
| dual interface (usb A / usb C) about 2 years ago, and it was
| usefull to just get some pictures off my phone. I usually don't
| rely on such a setup for long term but as with all things I was
| delayed tending to it. I figured there were 2 per box so i just
| copied them twice, and diffed them several times to make sure
| they were exact copies.
|
| After 24 months, one of the drives had a %95 loss, almost every
| picture was lost cut-off bottom half or so. The other drive
| surprisingly seemed fine, though it had been plugged in every 6-9
| months I recall, as I wanted to browse it a few times, it seems
| that this action saved the volume. Upon further inspection the
| good drive still lost 10 pictures in about 5 thousand, so it
| wasn't perfect.
|
| Lexar.
|
| https://www.ebay.com/itm/176810492981?chn=ps&_trkparms=ispr%...
| pixl97 wrote:
| Really who knows if you're getting a legit drive any longer...
|
| https://www.tomshardware.com/pc-components/ssds/fake-samsung...
| Giefo6ah wrote:
| > After 24 months, one of the drives had a %95 loss, almost
| every picture was lost cut-off bottom half or so.
|
| If these are JPEGs with a grey or green lower half, it's likely
| only a few 16x16 macroblocks are corrupted and you can recover
| the rest.
|
| This cannot be done programmatically because you have to guess
| what the average colour of the block was, but it can be worth
| it for precious pictures.
| havaloc wrote:
| I bought about 20 flash drives in 2019 at work to parcel out when
| needed, once or twice a quarter for users.
|
| I needed one last week, and had to throw most of them away, they
| had all died from presumably dormancy, even new in the package.
| foxglacier wrote:
| Beware that flash data lifetime is sensitive to temperature in
| the normal range people store stuff at. Store them in the roof
| space of your house that can exceed 40C each day and they might
| not last one year.
|
| Definitely not a medium to passively store anything long term
| without power! Use Hard drives or Blu-ray instead.
| jmb99 wrote:
| The linked post currently has demonstrated that 6 years in some
| reasonable-ish condition is perfectly fine.
|
| > they might not last one year.
|
| > Definitely not a medium to passively store anything long term
| without power!
|
| Do you have any evidence to back up this claim? I'm much more
| interested in data than fear mongering.
| foxglacier wrote:
| He stored them on a shelf which is probably 25C max. and that
| has an order of magnitude longer life than at 40C. [1]
|
| [1] https://www.ni.com/en/support/documentation/supplemental/
| 12/...
___________________________________________________________________
(page generated 2026-03-09 23:00 UTC)