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Old May 22nd 18, 08:51 AM posted to alt.comp.os.windows-10
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Default USB thumb drives.

On Tue, 22 May 2018 17:20:46 +1000, Lucifer Morningstar
wrote:

On Mon, 21 May 2018 19:30:36 +0100, "Jimmy Wilkinson Knife"
wrote:

On Mon, 21 May 2018 13:07:45 +0100, Paul wrote:

Jimmy Wilkinson Knife wrote:

Maybe that's why mine are slowing down - more cells are becoming weak?

The Toolkit software that comes with the drive,
should be able to provide statistics for you.
Like, how many blocks were spared out. If a block
cannot remember what you write to it, the drive
may decide to spare it out and replace it, just
like a hard drive would. This is automatic sparing
just like in the ATA designs.


I would have looked at the SMART data, but they're in a mirror array by the motherboard's hard disk controller, which I thought blocked that information.
But not on this controller apparently.
Not entirely sure how to interpret all this, but:

First SSD:
Raw Read error rate, value 100, worst 100, warn 0, raw 000000000005
Reallocated Sector count, value 100, worst 100, warn 0, raw 000000000000
Data Address Mark errors, value 23, worst 23, warn 0, raw 00000000004D

The others are either raw 000000000000 or marked as unimportant by the program speedfan, so I didn't type them in (it won't copy and paste).

Second SSD:
Raw Read error rate, value 100, worst 100, warn 0, raw 00000000000D
Reallocated Sector count, value 100, worst 100, warn 0, raw 000000000002
Data Address Mark errors, value 18, worst 18, warn 0, raw 000000000052

Speedfan reports (on the quick test) 100% performance, but 0% fitness?! I think the 0% may be it not reading the SMART correctly through the RAID controller, or it doesn't have a clue about some stats as there are no warnings apart from a red ! on an "unknown parameter".

The mark errors concern me, I'm assuming they also started at 100 and 0 means imminent failure. So 18 means it's 82% worn out?
The Acronis website says "Although degradation of this parameter can be an indicator of drive ageing and/or potential electromechanical problems, it does not directly indicate imminent drive failure."
Huh? If it's 82% aged, surely that's something to indicate failure soon?
I can't find anything certain on Google about "data address mark errors".

The kind of "weak" I'm referring to, is not permanently
damaged sectors. It's sectors that the charge is
draining off the floating gates in a matter of
a few months, rather than the ten years we would
normally expect. This was causing the read rate
on "data at rest" to drop. So if you wrote a backup
today on the device, it might read at 300MB/sec. If
two months from now, you tried to read the same big file
again, it would be reading at 180MB/sec. And it
does that, because the charge draining off the cells
corrupts them, and the powerful error correcting code
needs time to do the corrections to multiple bits
in the sector. The data is still officially "intact"
and error free, in that the error corrector isn't exhausted.

They "fixed" this in a firmware update, by having the
drive re-write the cells after three months (equals
degraded wear life and shortens the life of the drive).


As long as someone doesn't try to use it as long term storage and doesn't plug it in for 6 months. Or does it stay put if switched off?

On TLC, around 10% of storage is used for ECC bits, and
when QLC comes out, this is expected to grow.

At some point, adding ECC will affect storage capacity
sufficiently, we will have hit a wall on "extending the
number of bits stored in one cell". For example, if
you needed as many ECC bits as data stored, yes, you
doubled the capacity by going from QLC to the next thing,
but you cut the capacity in half by the need to use more ECC.
They can't keep increasing the bits per cell before
it bites them on the ass. The write cycles is dropping
with each generation too. Flash is becoming the equivalent
of silicon toilet paper.

In fact, doing some math the other day, I figured out
it was costing me $1 to write a Flash drive from
one end to the other.


That can't be right. Are you claiming a $100 drive can only be written completely 100 times?

There is a tangible wearout
on the highest density devices. And it's beginning
to equate to dollars. When I use a hard drive on the
other hand, I don't have such a notion. It's been
a long time since I lost a hard drive. I've got
a few that have bad SMART, but "they're not dead yet".
Some of the flaky ones have been going for an extra
five years after retirement (now used as scratch drives).


Actually I've had terrible trouble with hard drives but never ever had a single SSD fail, apart from OCZ **** that I very quickly stopped using.

The number of hard drives that either overheated or just started clicking.

There are just a few flash drives, that are huge and
the interface happens to be slow. There's a 30TB one,
you can continuously write it at the full rate, and it
is guaranteed to pass the warranty period :-)
So that would be an example of a drive, where
a lab accident can't destroy it. Because it
can handle the wear life of writing continuously
at its full speed (of maybe 300 to 400MB/sec).
If the 30TB drive was NVMe format, and ran at
2500MB/sec, it might not be able to brag about
supporting continuous write for the entire warranty
period. You might have to stop writing it once in
a while :-)


That would be a ****ing busy server to write that much data. And if you had such a server, you'd most likely need way more storage space, so each drive wouldn't be in continuous use.


SSDs are not used in servers due to their unreliability.


I was reading about a device in the lab stages that may turn digital
storage on its end. (if one chooses to believe corporate hype) It is
a crystal that's supposed to have the ability to store many petabytes
of data. The downside is that it can only be written to one time -
but the storage is so vast/fast/cheap in so small a space that it
could conceivably replace mechanical hard drives, by just opening up
another portion of the device and forgetting what is written in the
sectors you don't need anymore.
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