On Thu, 17 Dec 2020 20:32:35 +0000, bob prohaska wrote:

> It might be useful to re-frame the issue in terms of failure mode. If a
> machine fails gracefully, how long it's going to last becomes much less
> worrisome. If a storage device gives warning that it's running out of
> write capacity I might not be afraid of QLC vs lower-density options.
>
> If it just goes all bricklike, with no warning at all, it's a lot less
> attractive. Just the ability to test how much over-provisioning remains
> available would be a big help. SMART keeps some track of deterioration
> in mechanical drives, does it exist for SSDs?
>
Agree completely, which is why, so far I've avoided SSDs apart from one
case - I have a SanDisk 128GB one installed in an old Lenovo R61i laptop
that I'd had from new. After its hard drive died I was going to junk it
because it turned out that the HDD interfacing electronics were incapable
of supporting any HDD of more than 200GB - and at the time, 3 years ago,
it was impossible to buy any HDD smaller than 320GB. So, I picked up the
SanDisk, installed it threw 64 bit Fedora onto that and it all just
worked. The machine is now by "backup laptop" and has been running 24/7
running protein folding software since the start of the COVID lock-down
in March. For desk-toppy stuff the machine is now pleasingly faster that
it ever used to be, but for anything that needs grunt, lets just say the
1.6Ghz Core Duo is less than sprightly. Not even a hint of a problem with
the SSD though.

That said, Unless you're a scrupulous backer-upper to offline drive(s)
its probably worth paying a premium for your SSDs: I've heard that the
cheapies do suddenly lie down and die, i.e. loose or corrupt data, while
the better, more 'professionally' oriented  units switch to read-only
mode once they've accumulated enough faults to prevent further writes
without causing data loss.

=====
Being paranoid about such things, I my laptops ans server all have smartd
installed and configured to provide a weekly disk status report: I ran
the disk in the Lenovo R61i into the ground and had the disk in my house
server fail at almost the same time - both had around 50,000 hours on
them according to smartd - and in both cases smartd gave me just enough
warning to have replacement disks on the shelf when the live ones died -
and I didn't loose ant data either!

BTW, another benefit of using SSDs is that they accumulate runtime hours
a lot slower than HDDs - with my usage pattern, smartd shows that both my
main Laptop (active around 8-12 hours a day) and the house server (active
24/7) add around 20-30 hours a week to their disk's runtime, while the
R61i (active 24/7 doing protein folding) adds 1 hour (sometimes as much
as 2 hours) to its SSD runtime per week. If this is a general pattern,
and I think it may well be, then SSDs may have a longer clocktime life
than an HDD handling a similar workload.

This figures, since an HDD will tend to keep spinning after a burst of
activity, to minimise startup delays and head load/unload cycles, while
this stuff is not relevant for an SSD.

Needless to say, I'm very curious to know if any of you have had a
similar experience of the rate at which an HDD accumulates runtime hours
vs an SSD.


--
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Martin    | martin at
Gregorie  | gregorie dot org

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