What is so frustrating about SSDs is how very poorly they compare to previous incarnations of solid state storage.

Using Disk-On-Chip and/or IDE-pin-compatible CF cards, I had many, many devices in the field that lasted, mounted read-only, for decades An entire sect of the computing industry came to rely on these parts as alternatives to spinning media that could not mechanically fail.

This is not the case with SSDs at all. They fail left and right, even mounted read-only, for all manner of complicated and interesting reasons. It's very frustrating that SSDs are not a step forward in reliability from spinning media and are a step downward compared to (for instance) a 16MB consumer CF card from Sandisk, circa 2000.

rsync.net filers, which need a boot mirror, are always constructed with two unrelated SSDs - usually one Intel part and one Samsung part - so that when the inevitable usage-related failure occurs, it does not occur simultaneously to both members of the mirror which have, being a mirror, been subjected to identical usage-lives.[1]

We shouldn't have to do that.

[1] I can't overstate this - if you need a RAID mirror, do not use identical SSDs for the two members of the mirror. There are many, many cases of SSDs failing not due to "wear" or end-of-life, but due to weird usage edge cases that cause them to puke ... and in a mirror, you give the two parts identical usage ... we either get two different generations of Intel part (current gen and just-previous gen) or we get current Intel and current Samsung ...

But magnetic hard drives failed all the time. I have a giant stack in my office closet just from my dev machines over the years. But it wasn't new and scary -- it was just a hard drive failing -- so it was just normal. Some had controllers fail, suddenly blinking out of existence. Another had cache memory corrupt so it just gave ridiculous readings occasionally. Others had physical failures.

I don't know where to begin relative to prior flash memory (e.g. CF cards) which were absolutely notorious trash.

It is worth noting that every smartphone the world over has an "SSD" in it. We spend remarkably little of our mental power concerned about the flash storage. It is the cause of a negligible amount of device failures.

That would almost certainly be small-block SLC flash rated for 100K program/erase cycles and 10 years of retention. The huge-block TLC now is ~1K program/erase cycles and 2-3 years of of retention depending on where you look (the manufacturers are not surprisingly quite reluctant to release these specs...)

Also, though, because most serious RAIDs contain more drives than you can find manufacturers of hard drives.

The tradeoff from worse read disturb characteristics is NAND that is 100x cheaper per GB than in 2000.

I don't know about that. I know most managers in embedded software go cheap on engineers and software assurance on purpose to get bonuses and such. The hardware side makes me think you haven't studied deep, sub-micron hardware much. I started looking into it a few years ago or so, just reading the slides on lots of stuff even though not understanding much of it. They helpfully put a lot in lay terms, though, with lots of comparisons. To say the stuff gets harder every time you shrink to a smaller node is an understatement, esp for solid state.

If anything, the modern flash should probably be considered broken right as they ship out of the factory. If not, the process nodes after 90nm or so just keep having more and more ways for individual components to screw up or change behavior across same wafer. Some happen instantly by design. Some happen later with aging. The memory technologies are closer to that analog level of things than most with harder verification. The high-density flash on newer nodes uses less-reliable tech than most just to operate at that low cost. So, they add all kinds of firmware and hardware tricks to try to make it work for a period of time like it's a whole, functional unit of storage despite pieces of it misbehaving all throughout.

It's a nice, man-made miracle these techs even work at all. Those that last longer like you mentioned still exist. I'll add a comment with links to one type so you can compare price/storage/performance to these broken-by-design SSD's you use. I'll throw in another two that mention shrinking challenges so you can see what they face every time they have to upgrade or just deploy new designs in mixed-signal.

https://news.ycombinator.com/item?id=18528023

https://www.electronicdesign.com/digital-ics/understanding-2...

https://anysilicon.com/ic-design-impact-in-moving-from-28nm-...

So the combination of non-moving parts (making it hard/impossible to debug via physical inspection) combined with a tons of wear leveling/misc magic can defo make it seem like SSD's are magical.

ZFS has shown that removing layers of abstraction with regard to storage can be beneficial.

It would be an interesting product to have, a raw block API to a Flash device with all the temporary state stored on the host - but a hard one to sell, as it's not differentiated in any way.

Besides, I don't think manufacturers want to release the best practices for using their memory.

https://www.youtube.com/watch?v=C5JoC4-qsO0 https://www.forensicswiki.org/wiki/Solid_State_Drive_(SSD)_F...

Because they don't die incrementally. Wtih a hard disk you'll get bad sectors, growing slowly over time. Or a head crash and then it's all dead.

What could cause an entire SSD to die at once? I would totally understand bad sectors, but the whole thing at once? Where it doesn't even try to read existing data?

Firmware -- undebuggable, unobservable, unfixable software, jammed into your devices -- is the enemy.

A component failing? Electrical components fail. Sometimes it's a manufacturing defect, sometimes a design defect, sometimes something under or over-volted and it was enough to cause damage to any given component.

Could be an IC, could be a capacitor, could be a poorly laid trace. A poorly shielded RF source could even damage any number of components.

I mean, in theory a single high charge particle from that rare cosmic ray that reaches the surface of earth running full-steam-ahead through an IC could cause just the right amount of damage to make it fail although this would be an incredibly improbable scenario.

Same goes for HDDs, televisions, your clock radio, whatever.

SSD has a problem in that almost every failure case looks more like a head-scratch than a bad sector.

Even the most local problem that is excessive writing on a sector can take the entire chip down.

That wire is the one delivering power. Point being, while things are so complicated that you often can have a lot going on and still try things, there are still single points of failure that can never be fully covered.

In a mechanical hard drive, there are moving parts which can wear out due to friction, etc.

SSDs are solid-state, so it seems like at least theoretically, it should be possible to build one that keeps working for decades. e.g. I have solid-state hardware from the 70s and 80s which still functions.

I've always been a little mystified as to why SSDs' data areas wear out for that reason,[1] but that's a whole separate issue. The author of the article is writing about sudden failure of the device as a whole.

There are only two explanations I've ever heard for short lifetimes in electronics as a general industry.[2]

For devices manufactured after about 2000 there's tin whiskers,[3] which began to be a problem because of RoHS requirements. I'm not sure if that applies here, though.

If the device includes electrolytic capacitors, my understanding is that those generally have a finite lifetime as well, and it can be fairly short if they're poorly-made.

I'm not a hardware expert, though, so I'd be interested in hearing about other factors, and I'm sure the author of the article would too.

[1] I've seen lots of writeups of how wear-leveling works, etc., but never a good physical explanation of what is actually wearing out over time.

[2] Obviously there are other factors for specific devices, or specific designs. E.g. maybe parts of a specific device break over time due to thermal expansion and contraction if the device wasn't engineered to handle that properly.

[3] https://nepp.nasa.gov/whisker/background/

SSDs are flash are basically EEPROMs. In an EEPROM one bit is stored in a dual-gate MOSFET. One Gate is a normal gate, the other is floating, i.e. it just is a small conductive island. The information is stored by (quite literally) shooting electrons through the insulation of the floating gate into it. They're then trapped on the gate; if you turn the second gate on, the transistor conducts iff the floating gate is also turned on. This shooting action happens to damage the insulation, which at some point is degraded enough that it can't keep the electrons trapped on the floating gate. Hence the electrons leave, together with your information.

> For devices manufactured after about 2000 there's tin whiskers,[3] which began to be a problem because of RoHS requirements.

The solder joints themselves usually don't form whiskers, which mostly grow on pure tin-plated surfaces, e.g. the pins of components (which previously used lead). Using lead-free solder is mostly co-incident with whisker risk, not the cause of the majority of problems.

If I keep my SSD 40 degrees cooler with a freezer, will it last an indefinite number of write cycles?

EDIT: More reasons and methods for failure of "solid state" circuits and systems: https://news.ycombinator.com/item?id=14765868

there's a reason companies don't repair circuit boards in consumer electronics.

It doesn't seem plausible to have a business case where you'd get be able to get a large quantity of identical boards (that are otherwise good!), replace caps on them, and be able to sell them for much more than you got them - i.e. that the boards haven't become obsolete in that time. If there's no mass production, there's not much use for automation.

Indeed, that is the question that the article's author seems to be asking.

That defect doesn't strike me as being inherently related to SSD media, but really left a bad taste in my mouth with what might be going on in the development process to lead to such instability.