* On 2021 29 Sep 09:47 -0500, Reco wrote: > Hi. > > On Wed, Sep 29, 2021 at 07:59:50AM -0500, Nate Bargmann wrote: > > A test run with KDE Plasma shows that performance is acceptable even > > with EXT4 as the file system. I now have some SanDisk Ultra Fit flash > > drives arriving in 128GB capacity (overkill, oh well). I am now > > considering what file system would be proper to use in this case. > > A plain ext4 with the 'discard' mount option will do just fine.
From the ext4(5) man page:
discard/nodiscard
Controls whether ext4 should issue discard/TRIM commands to the
underlying block device when blocks are freed. This is useful
for SSD devices and sparse/thinly‐provisioned LUNs, but it is
off by default until sufficient testing has been done.
LUN? That's new to me. Let's see[1]:
"In computer storage, a logical unit number, or LUN, is a number used to
identify a logical unit, which is a device addressed by the SCSI
protocol or by Storage Area Network protocols that encapsulate SCSI,
such as Fibre Channel or iSCSI."
On this desktop I run a cron job twice a month that runs fstrim(8) that
its man page states:
Running fstrim frequently, or even using mount -o discard, might nega‐
tively affect the lifetime of poor‐quality SSD devices. For most desk‐
top and server systems a sufficient trimming frequency is once a week.
Note that not all devices support a queued trim, so each trim command
incurs a performance penalty on whatever else might be trying to use
the disk at the time.
That leads me to think that discard could be problematic on some
devices. Does a USB flash drive fall into that category? I've no
problem using anacron to run an fstrim(8) job every so often if discard
is thought to be too aggressive.
> > I understand that the journal can be disabled when using EXT4 to save
> > writes which is probably fine (this system will be non-critical).
>
> It's possible to do, but it is not needed that much.
> If you're trying to conserve drive's resources - just write less on it.
> I.e. redirecting .xsession-errors to /dev/null, removing that annoying
> /var/log/journal directory, adding a good set of filters to rsyslog,
> etc.
>
> For instance, this low-cost SSD that I use in my laptop endured about
> 1.8 Tb writes over 3.5 year usage, and shows no signs of degradation.
Presumably there is a difference between an SSD which expects a lot of
writes and a USB flash drive that expects relatively few by comparison
used in the role of an SSD/HDD, not?
- Nate
[1] https://en.wikipedia.org/wiki/Logical_unit_number
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