Debian-Pi-Aarch64/docs/external_usb_ssd_UAS.md

Example

UGREEN

• Port: USB 3.0 2.5-Inch SATA
• Mode/PID: CM237
• Main Controller: ASM1153E (Very important, not all drive support HAS, this Model CM237 has tested that was supported.)
• Support: UASP Transfer Protocol

OPEN Trim for external usb ssd

1. Check TRIM support**

sudo fstrim -v /

fstrim: /run/media/telgar/ssd: the discard operation is not supported

$ lsblk --discard /dev/sda
NAME   DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
sdb           0        0B       0B         0
├─sda1        0        0B       0B         0
└─sda2        0        0B       0B         0

If the DISC-MAX value is 0B, then TRIM is not enabled.

2. Enable TRIM

Find the USB idVendor and idProduct :

$ lsusb
...
Bus 002 Device 002: ID 174c:1153 ASMedia Technology Inc. ASM1153 SATA 3Gb/s bridge
...

Add /etc/udev/rules.d/50-usb-ssd-trim.rules

ACTION=="add|change", ATTRS{idVendor}=="174c", ATTRS{idProduct}=="1153", SUBSYSTEM=="scsi_disk", ATTR{provisioning_mode}="unmap"

Then reboot, the TRIM will be enabled.

3.Fstrim the SSD device

1'st time, run "fstrim -v /" successfully:

$ sudo fstrim -v /
/: 111.4 GiB (119574462464 bytes) trimmed

$ lsblk --discard /dev/sdb
NAME   DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
sda           0      512B       4G         0
├─sda1        0      512B       4G         0
└─sda2        0      512B       4G         0

4.Automatic trimming

The last thing you will need to do to make sure the TRIM command is run automatically in the background

(so you don't need to run fstrim manually) is to enable the built-in fstrim.timer.

To do that, run the command:

$ sudo systemctl enable fstrim.timer

By default, it will run weekly.

--

All done.