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Unpowered SSDs slowly lose data

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Re: Unpowered SSDs slowly lose data

#271

Post by Sohcahtoa82 »

userbinator wrote: post #168
ACCount37 wrote: post #162

Earlier quoted context omitted.

Because no one is willing to pay for SLC. Those QLC NAND chips? Pretty much all of them have an "SLC mode", which treats each cell as 1 bit, and increases both write speeds and reliability massively. But who wants to have 4 times less capacity for the same price?

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…

> But why won't the manufacturers let you choose? The real answer is clearly planned obsolescence.

No, it's not. The real answer is that customers (Even B2B) are extremely price sensitive.

Look, I know the prevailing view is that lower quality is some evil corporate plan to get you to purchase replacements on a more frequent basis, but the real truth is that consumers are price sensitive, short sighted, and often purchasing without full knowledge. There's a race to the bottom on price, which means quality suffers. You put your typical customer in front of two blenders at the appliance store, one is $20 and the other is $50, most customers will pick the $20 one, even when armed with the knowledge that the $50 version will last longer.

When it comes to QLC vs SLC, buyers don't care. They just want the maximum storage for the smallest price.

Re: Unpowered SSDs slowly lose data

#272

Post by mort96 »

lazide wrote: post #255
jeremyvisser wrote: post #218

Earlier quoted context omitted.

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.

We're not talking about the SSD controller dying. The SSD controller in the hypothetical situation that's being described is working as intended.

Re: Unpowered SSDs slowly lose data

#273

Post by mort96 »

userbinator wrote: post #168
ACCount37 wrote: post #162

Earlier quoted context omitted.

Because no one is willing to pay for SLC. Those QLC NAND chips? Pretty much all of them have an "SLC mode", which treats each cell as 1 bit, and increases both write speeds and reliability massively. But who wants to have 4 times less capacity for the same price?

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…

> do you want to have 4x more capacity at 1/100th the reliability?

Yes.

QLC SSDs are reliable enough for my day-to-day use, but even QLC storage is quite expensive and I wouldn't want to pay 4x (or realistically, way more than 4x) to get 2TB SLC M.2 drives instead of 2TB QLC M.2 drives.

Re: Unpowered SSDs slowly lose data

#274

Post by mort96 »

mkesper wrote: post #190
pbmonster wrote: post #163

Earlier quoted context omitted.

Sure. Just make sure the drive is warm before you take it out of the container - because this is when the critical condensation happens: you take out a cold drive an expose it to humid room temperature air. Then water condenses on (and in) the cold drive. Re-freezing is also critical, the container should contain no humid air when it goes into the freezer, because the water will condense and freeze as the container c…

A vacuum sealer would probably help to avoid the humid air, too.

Only if you wait for the drive to heat up before you remove the vacuum seal.

Re: Unpowered SSDs slowly lose data

#275

Post by mort96 »

bullen wrote: post #153
karczex wrote: post #142

Earlier quoted context omitted.

That's how it has to work. To increase capacity you have to make smaller cells where charge may easier diffuse from one cell to another. Also to make drive faster, stored charge has to be smaller, which also decrease endurance. With SLC and QLC comparison is even worse as QLC is basically clever hack to store 4 times more data in the same number physical cells - it's tradeoff.

Yes, but that tradeoff comes with a hidden cost: complexity! I much rather have 64GB of SLC at 100K WpB than 4TB of MLC at less than 10K WpB. The spread functions that move bits around to even the writes or caches will also fail. The best compromise is of course to use both kinds for different purposes: SLC for small main OS (that will inevitably have logs and other writes) and MLC for slowly changing large data like…

My problem is: I have more than 64GB of data

Re: Unpowered SSDs slowly lose data

#276

Post by thenthenthen »

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 is the goldielocks area here, spinning rust? My 20 year old ide hdds seem to be… ok

Re: Unpowered SSDs slowly lose data

#277

Post by ralferoo »

xhkkffbf wrote: post #262
mrspuratic wrote: post #228

Earlier quoted context omitted.

CD storage has an interesting take, the available sector size varies by use, i.e. audio or MPEG1 video (VideoCD) at 2352 data octets per sector (with two media level ECCs), actual data at 2048 octets per sector where the extra EDC/ECC can be exposed by reading "raw". I learned this the hard way with VideoPack's malformed VCD images, I wrote a tool to post-process the images to recreate the correct EDC/ECC per sector.…

Octets? Don't you mean "bytes"? Or is that word problematic now?

Personally, I prefer the word "bytes", but "octets" is technically more accurate as there are systems that use differently sized bytes. A lot of these are obsolete but there are also current examples, for example in most FPGA that provide SRAM blocks, it's actually arranged as 9, 18 or 36-bit wide with the expectation that you'll use the extra bits for parity or flags of some kind.

Re: Unpowered SSDs slowly lose data

#279

Post by theragra »

xhkkffbf wrote: post #262
mrspuratic wrote: post #228

Earlier quoted context omitted.

CD storage has an interesting take, the available sector size varies by use, i.e. audio or MPEG1 video (VideoCD) at 2352 data octets per sector (with two media level ECCs), actual data at 2048 octets per sector where the extra EDC/ECC can be exposed by reading "raw". I learned this the hard way with VideoPack's malformed VCD images, I wrote a tool to post-process the images to recreate the correct EDC/ECC per sector.…

Octets? Don't you mean "bytes"? Or is that word problematic now?

I wonder if OP used "octets" because physical pattern in the CD used to represent a byte is a sequence of 17 pits and lands.

BTW, byte size during the history varied from 4 to 24 bit! Even now, based on interpretation, you can say 16 bit bytes do exist.

Char type can be 16 bit on some DSP systems.

I was curious, so I checked. Before this comment, I only knew about 7 bit bytes.

Re: Unpowered SSDs slowly lose data

#280

Post by unethical_ban »

Sohcahtoa82 wrote: post #271
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…

> But why won't the manufacturers let you choose? The real answer is clearly planned obsolescence. No, it's not. The real answer is that customers (Even B2B) are extremely price sensitive. Look, I know the prevailing view is that lower quality is some evil corporate plan to get you to purchase replacements on a more frequent basis, but the real truth is that consumers are price sensitive, short sighted, and often pur…

For your specific example, I would buy the $20 because I would assume the $50 is just as bad.

Having built computers casually for some time, I never recall being told by the marketing department or retailer that one kind of SSD was more reliable than another. The only thing that is ever advertised blatantly is speed and capacity. I saw the kind of SSD sometimes, but it was never explained what that meant to a consumer (the same way SMR hard drives were never advertised as having slow reads)

If I saw "this kind of SSD is reliable for 10 years and the other one is reliable for 2" then I may have made a decision based on that.

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