SATA SSD USB Enclosure

You need to be careful when picking an USB enclosure for your SATA SSD drive: the problem is that not every USB enclosure supports the SATA TRIM / USB UNMAP command, which is a must for keeping your SSD healthy.

When browsing the internet, I’ve found that the JMICRON JMS578 chipset does support TRIM. Therefore I’ve purchased cBox T23M USB 3.1 which uses the JMS578 chipset.

Indeed, plugging the enclosure into my computer and running lsblk confirmed that the enclosure supports TRIM:

$ lsblk --discard
sdc           0        4K       4G         0
├─sdc1        0        4K       4G         0
└─sdc2        0        4K       4G         0

However, some older enclosures using the JMS578 chipset with older firmware may not support TRIM. In such case you need to upgrade the firmware of your JMS578 chipset.

Even though JMicron doesn’t claim that JMS578 supports UNMAP/TRIM directly, it states support for UASP specification which lists the “Enables TRIM (UNMAP in SCSI terminology) operation for SSDs” as one of its goals. Therefore, when searching for an enclosure, make sure it either:

  • Explicitly states TRIM support, or
  • Explicitly states UASP support, or
  • Uses a chipset which supports UASP or TRIM, such as JMS578.
Written on September 16, 2020