On 10/03/2021 11.34, Paul wrote:
Carlos E.R. wrote:


Even leaving aside Jeff's point about bits versus bytes, speed
isn't the only important parameter for and SSD: there are
probably many, but the one that bugs me is the tolerated number
of writes - which for the same size SSD in the same machine/use,
more or less maps to lifetime. You also need to know how they
behave when they reach their end of life: do they continue trying
to work (I don't think any), switch to read-only, or just become
a brick (at least one make/range does).

Which one bricks? That's important to know.


Intel SSDs stop both reads and writes, when the wear life is
exceeded. Once the wear life hits, say, 3000 writes per location, the
drive stops responding. This makes it not possible to do a backup or
a clone.

Ok. I will have to check it I have any Intel, I don't remember.


Sure, of course one must have a backup, but even if one does a daily
backup (which most people don't), the incident can happen just after one
saves important files. And as typically the computer bricks, it is not
possible to save the file elsewhere. At best, the day work is lost.



As a consequence, the user is advised to keep a Toolkit handy which
has an end-of-life predictor, for better quality handoff.

Sorry, Toolkit? What is that? Ah, you mean that one must have
"something" that predicts life. True.


Of course your drive is not near end of life. But, you only know the
wear rate, if you check the Toolkit occasionally for the projections
on life. And, you look pretty bad, if the topic slips your mind, and
you start asking for help with that "too crusty backup I made two
years ago". We don't want this topic to be handled by people losing
data.

It's a shame, that several of the toolkits, suck. I was not impressed
with a couple I checked. Hobbyists could write better code - code
that displayed the salient data to keep users informed.

And a drive I could not keep because the hardware sucked, the toolkit
was great. That's just how this computer stuff works.


On the Windows side of my laptops I don't have anything. On the Linux
side I have the smartctl daemon, but I don't know what it says about end
of life warnings. It might send an email. Otherwise, it will be in the
warning log.



*******

The point of making an example out of Intel, is to make you aware of
what the most extreme policy is. And Intel wins the prize in this
case. Some products from competitors, will allow you to read, and
they stop writing. This allows you to make a backup using a Macrium
CD, and prepare a replacement SSD.

Right.

The reason Intel stops reading, is to guard against the possibility
that read errors are not getting detected properly. Intel
arbitrarily decided that only "perfect" data need apply. And they
weren't going to allow a certain BER to leak out and then customers
blame Intel for "accepting corrupt data".

heh.


One of the BER indicators in the SSD datasheets, is 10x less good
than a hard drive (one product might be 10^-15, the other 10^-14 kind
of thing). And you may find review articles making references to
this, that this difference is a bad thing.

The ECC on SSDs is already a pretty heavy weight item. A bit more
than 10% of flash cells, are likely being used just to hold the ECC.
And it's that ECC calc that keeps TLC flash from ruining our data.
One of the first TLC drives, every sector had errors, and it was the
ECC that transparently made the drive look "perfect" to the user.
When this happens, the drive can slow down (ECC done by ARM cores,
not hardware), and this makes the more aggressive storage techs (QLC
flash) look bad. It's the "stale slow" drive problem - one way to fix
it, is for the drive to re-write itself at intervals, which of course
depletes the wear life.

The topic is a lot like BEV (electric) cars :-) "Different, in a bad
way" :-) The populace will know, when everyone has had the mechanic
tell them "your battery pack needs to be replaced".

Paul

{chuckle}

--
Cheers, Carlos.