Re: [gentoo-user] Finally got a SSD drive to put my OS on

[Mark Knecht <markknecht@gmail.com>]

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On Sun, Apr 16, 2023 at 3:18 PM Frank Steinmetzger <Warp_7@gmx.de> wrote:
>
> Am Sun, Apr 16, 2023 at 01:22:32PM -0700 schrieb Mark Knecht:
> > Frank,
> >    Thank you for the in-depth explanation.
> >
> >    I need to do some study before commenting further other than to say
> > so far I'm finding different comments depending on whether it's
> > an SSD or an M.2 drive.
>
> Uhm, I think you mix up some terms here. An M.2 drive *is* an SSD
> (literally, as the name says, a solid state drive). By “SSD”, did you mean
> the classic laptop form factor for SATA HDDs and SSDs?
>
> Because M.2 is also only a physical form factor. It supports both NVMe and
> SATA. While NVMe is more modern and better suited for solid state media
and
> their properties, in the end it is still only a data protocol to transfer
> data to and fro.
>

No, I don't believe I've mixed them up but if you see something I'm wrong
about
let me know.

When I speak of SSDs I do mean devices that are marketed as SSDs &
probably use SATA.

When I speak of M.2 I mean what you and I both call M.2.

While SSD & M.2 are both Flash devices they don't  provide the same info
when queried by smartctl which makes a direct comparison more
difficult.

Depending on the manufacturer & the foundry they build the chips in the
technologies in these devices can be quite different independent of whether
they are M.2 or SSD.

1) Dale's Samsung 870 EVO - V-NAND TLC (8-bits/cell) and 600TB written
2) My Crucial 1TB M.2 is QLC (16 bits/cell) and 450TB written
3) My Sabrent 1TB M.2 is TLC (8 bits/cell) and 700TB written
4) My Crucial 250GB is unknown because Crucial sells 5 versions
that come from different fabs and have different specs.

All 4 drives are warranted for 5 years or hitting the TB written value.

All 4 drives have 16K page sizes.

That said, I've been using the Crucial on my Kubuntu dual boot for over a
year and only have 28TB written so I'm a long way from the 450TB spec and
likely won't come close in 5 years. (If I'm even still using this machine.)

On the Windows side which I use far less I've only written about 2TB total.

In my case the workloads are generally fairly large files. They are
generally
either 24MB photo files for astrophotography or audio recording files which
are typically 50-100K. Neither of them are 'modified' and need to be
rewritten. They are either saved or deleted.

Whether the write amplification makes a difference or not in real life
I don't know. I'm sure for some work loads it does but the 'percent
used' value that smartctl returns is 2% for the Crucial and 0% for
the Sabrent so both appear to have a lot of life left in them.

Mark

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