I just bought a SATA SSD and a USB-SATA adapter. I chose an adapter with UASP support, because I thought it would make it possible to run a TRIM/DISCARD command, and I think it is important for the lifetime of the SSD.
When I connect the adapter to my Debian-based computer, the linux kernel detects it as expected and enables communication with the UAS protocol. Here is what the kernel reports:
[23886.083296] usb 2-1: new SuperSpeed Gen 1 USB device number 6 using xhci_hcd
[23886.104497] usb 2-1: New USB device found, idVendor=174c, idProduct=55aa, bcdDevice= 1.00
[23886.104508] usb 2-1: New USB device strings: Mfr=2, Product=3, SerialNumber=1
[23886.104513] usb 2-1: Product: 00SSD1
[23886.104518] usb 2-1: Manufacturer: CT500MX5
[23886.104522] usb 2-1: SerialNumber: 12345678D9DA
[23886.110042] scsi host1: uas
[23886.110883] scsi 1:0:0:0: Direct-Access CT500MX5 00SSD1 0 PQ: 0 ANSI: 6
[23886.111967] scsi 1:0:0:0: Attached scsi generic sg1 type 0
[23886.112698] sd 1:0:0:0: [sdb] 976773168 512-byte logical blocks: (500 GB/466 GiB)
[23886.112702] sd 1:0:0:0: [sdb] 4096-byte physical blocks
[23886.112841] sd 1:0:0:0: [sdb] Write Protect is off
[23886.112846] sd 1:0:0:0: [sdb] Mode Sense: 43 00 00 00
[23886.113013] sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[23886.113224] sd 1:0:0:0: [sdb] Optimal transfer size 33553920 bytes not a multiple of physical block size (4096 bytes)
lsusb confirms that the uas driver is used:
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/7p, 5000M
|__ Port 1: Dev 6, If 0, Class=Mass Storage, Driver=uas, 5000M
But I can’t run blkdiscard on this device:
# blkdiscard -f /dev/sdb
blkdiscard: /dev/sdb contains existing partition (dos).
blkdiscard: Operation forced, data will be lost!
blkdiscard: /dev/sdb: BLKDISCARD ioctl failed: Operation not supported
lsblk confirms that the block device does not support discarding:
# lsblk -D /dev/sdb
NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
sdb 0 0B 0B 0
`-sdb1 0 0B 0B 0
Where does the problem come from? Is there any hope I can run TRIM/DISCARD with this setup?
