[Discuss] External USB bridge to SSD

[worley at alum.mit.edu (Dale R. Worley)]

I've been trying to get "trim" to work on an SSD attached to my computer
with an external USB bridge.  The manufacturer's spec sheet says the SSD
supports trim.  (It also claims a lifetime of 360 times the disk
capacity as the write volume.)  I've used various tricks to get the
kernel and LVM to consider that trim is available.

https://wiki.archlinux.org/title/Solid_state_drive
https://askubuntu.com/questions/262154/trim-and-ssd-with-usb-3-0-enclosure-does-not-work-uasp-not-supported

    $ lsblk --discard /dev/sdb
    NAME                  DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
    sdb                          0      512B       4G         0
    ??????sdb1                       0      512B       4G         0
    ??????sdb2                       0      512B       4G         0
    ??????sdb3                       0      512B       4G         0
      ??????Hobgoblin01-User2        0      512B       4G         0

But I still can't execute the trim:

    # fstrim -v ./
    fstrim: ./: the discard operation is not supported

It looks like the problem is that the bridge chipset doesn't pass
through the trim operation.

I suppose next time I buy a USB/disk bridge, I should check that it says
that it implements trim!

Dale