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Why I'm usually unnerved when modern SSDs die on us

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Re: Why I'm usually unnerved when modern SSDs die on us

#201

Post by spatular »

shittyadmin wrote: post #2

I've experienced a few seriously strange issues with modern SSDs, even some of the better ones. I had a 512GB Samsung drive that became very slow randomly at doing IO operations, the whole machine would die for 10-30 seconds at a time once or twice a day while any process that tried to use the disk became blocked on IO. Then it'd come right back like everything was perfectly fine. Issues like this definitely worry me…

If on Linux, try running fstrim from time to time. More free space makes life of SSD's garbage collector / defragmenter much easier. I've anecdotally noticed that running fstrim reduces freezeups under heavy load from 1-2s to almost nothing on my Toshiba drive.

Re: Why I'm usually unnerved when modern SSDs die on us

#202

Post by userbinator »

rsync wrote: post #41
Waterluvian wrote: post #5

"When a HD died early, you could also imagine undetected manufacturing flaws that finally gave way. With SSDs, at least in theory that shouldn't happen" Why shouldn't it? Isn't it just hardware too? "With spinning HDs, drives might die abruptly but you could at least construct narratives about what could have happened to do that" Why can't you do the same with SSDs? It feels like the author's main complaint is the fr…

"It feels like the author's main complaint is the frustration of not understanding SSD hardware as well." 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…

compared to (for instance) a 16MB consumer CF card from Sandisk, circa 2000.

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...)

Re: Why I'm usually unnerved when modern SSDs die on us

#203

Post by blincoln »

falcolas wrote: post #57
blincoln wrote: post #47

Earlier quoted context omitted.

Why shouldn't it? Isn't it just hardware too? 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…

On 1): It's because each cell is essentially a consumable with a limited number of state transfers. It's similar in that way to how a solid state accellerometer still has a moving part inside it that can break or wear out over time. EDIT: More reasons and methods for failure of "solid state" circuits and systems: https://news.ycombinator.com/item?id=14765868

I understand that there is something that makes the cells stop working over time. blattimwind's reply is the first actual explanation I've ever seen of what that something might be.

Re: Why I'm usually unnerved when modern SSDs die on us

#204

Post by userbinator »

0db532a0 wrote: post #152
blattimwind wrote: post #134

Earlier quoted context omitted.

> 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. 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 electrons aren't shot through the insulation. They end up in the floating gate by quantum tunneling. The insulation by its name is non-conductive, and must be so that the electrons stay put. The degradation happens through general thermal wear.

The exact wear mechanism doesn't really matter (you must be referring to "hot carrier injection") --- the point is that to record data, electrons are being forced through a material which gradually wears it out.

Re: Why I'm usually unnerved when modern SSDs die on us

#205

Post by userbinator »

nneonneo wrote: post #29

A major problem with SSDs seems to be “firmware death” - where the flash chips are physically fine (or mostly fine), but the firmware (or firmware memory) has gotten corrupted due to some programming error, electrical glitch, or cosmic ray. I’ve had scores of older SSDs die after things like power outages and sudden shutdown events. This is super frustrating because the data is physically OK but the controller just i…

but the firmware (or firmware memory) has gotten corrupted due to some programming error, electrical glitch, or cosmic ray.

A lot of SSDs also store their main firmware in the same flash that is used to hold user data... this is something which was done with hard drives too (hence why dead/dying HDDs sometimes show up as a small drive with a weird name --- that's the "recovery mode").

Re: Why I'm usually unnerved when modern SSDs die on us

#207

Post by londons_explore »

bacon_waffle wrote: post #192
monocasa wrote: post #184

Earlier quoted context omitted.

For those doubting you, the going rate for embedded engineers out here in the Denver area where a lot of these SSD controllers are designed is ~$90k. Embedded engineers get peanuts for some reason.

I've noticed the same thing, and suspect that it's related to the way that higher level software scales compared to embedded. If a line of code is written to run in a customer's browser, then that line of code may be deployed to millions, maybe billions, of customers. But, if an equivalent line of code goes in to firmware for some widget, then you're doing pretty good to get that line in to a million widgets at all,…

Write an embedded bootloader and there's a good chance your code will be used by a billion people within a few years of writing it.

You'll still get paid peanuts for doing it.

Re: Why I'm usually unnerved when modern SSDs die on us

#208

Post by lake99 »

bacon_waffle wrote: post #192
monocasa wrote: post #184

Earlier quoted context omitted.

For those doubting you, the going rate for embedded engineers out here in the Denver area where a lot of these SSD controllers are designed is ~$90k. Embedded engineers get peanuts for some reason.

I've noticed the same thing, and suspect that it's related to the way that higher level software scales compared to embedded. If a line of code is written to run in a customer's browser, then that line of code may be deployed to millions, maybe billions, of customers. But, if an equivalent line of code goes in to firmware for some widget, then you're doing pretty good to get that line in to a million widgets at all,…

I agree with your comment about scaling, but I think you have underestimated the firmware deployment figures.

Ultimately, whatever we write that goes into firmware is hidden from the customer. The customer pays a price per unit, and other hardware vendors are competing against your product. This competition keeps the overall cost low. Except at the very top level like Intel or Samsung, semiconductor manufacturers seem to be fighting one financial crisis after another.

Competition does not work like that in Software. The products (even in the same domain) are all too different from each other, so though they may be competitors, they are rarely in direct competition.

Re: Why I'm usually unnerved when modern SSDs die on us

#209

Post by rasz »

pbhjpbhj wrote: post #51
blincoln wrote: post #47

Earlier quoted context omitted.

Why shouldn't it? Isn't it just hardware too? 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…

On the subject of capacitor death. Is there a robotic device that can take in a circuit board and swap out all the [electrolytic] caps?

Yes, and it mostly speaks Ukrainian, or Chinese.

Re: Why I'm usually unnerved when modern SSDs die on us

#210

Post by zanny »

vermilingua wrote: post #186
monocasa wrote: post #184

Earlier quoted context omitted.

For those doubting you, the going rate for embedded engineers out here in the Denver area where a lot of these SSD controllers are designed is ~$90k. Embedded engineers get peanuts for some reason.

~$90k is now peanuts. Interesting.

If you took the doubling of productivity since 1975 and inflation adjusted the median income from then ($7750) you would get about $68,000. In practice wages haven't risen against productivity and GDP so the real figure is $45,000.

To make it look even worse, the GDP tripled but population only rose 50%, so if you adjusted wages against total economic growth instead of productivity median should be around $110,000. Median.

So yes, $90k is pretty much peanuts for how much money an embedded engineer would be on average making for their employer.

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