First of all, I am pretty surprised my usb flash device supports trim:
sudo hdparm -I /dev/sdb | grep 'Model\|TRIM'
Model Number: SanDisk SSD CZ80 32GB * Data Set Management TRIM supported (limit 8 blocks) * Deterministic read data after TRIM
The usb stick is formatted with ext4. So according to hdparm, trim should work. However when I switch to the device and run:
sudo fstrim ./
it gives me:
fstrim: ./: FITRIM ioctl failed: Operation not supported
So what could be the issue here? Does hdparm lie about trim support, or could there be an other issue? Who to ask to debug such issues? (Info: fstrim works very well with my internal ssd).
Full output of
hdparm -I /dev/sdb can be found here: http://paste.ubuntu.com/6944144/