[arch-general] ssd trim using fstrim.service and fstrim.timer

[Leonid Isaev]

On Sun, Dec 27, 2015 at 09:45:27PM -0500, Francis Gerund wrote:
> Per the Arch wiki SSD page, I just enabled sysctl fstrim.timer, and then
> rebooted.  I did not "enable" fstab.service.  Now fstrim.timer is loaded,
> and active (but "waiting") and fstrim.service is loaded, but inactive.  And
> the time stamp file the wiki mentions has a "0" size.

In /var/lib/systemd/timers? They all have zero size, it's their timestamp what
matters.

> So, do I have to wait (A WEEK!) to see if it works, or can I somehow now
> run fstrim.service manually to at least get it done once?

fstrim.service most likely ran on-boot, silently, so you haven't noticed. If
you use systemd-journal, check it, otherwise just start fstrim.service w/o
enabling it (or run its ExecStart cmdline).

> Note: I could just add "discard" to /etc/fstab, but wouldn't that wear out
> the SSD faster than periodic trimming?

I don't know precise numbers, but IME none of those made a difference
performace-wise. I'd say if SSD wear is a problem (i.e. if you estimate it
within expected usage time of the device), just switch to a HDD.

HTH,
-- 
Leonid Isaev
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