Soft-resetting SATA devices in Linux

There are times when devices fail, or lock up.

In some of those cases it could be a SATA hard disk locking up (perhaps it is developing bad blocks, perhaps it just had a power failure due to a bad connector and got left in an undefined state).

Thankfully, Linux offers you vast control over the hardware.

To reset a SATA device, start by figuring out which logical port the drive is connected to:

# readlink /sys/block/sdX
../devices/pci0000:00/0000:00:1f.2/host1/target1:0:0/1:0:0:0/block/sr0

Force disconnect the device:

# echo 1 > /sys/block/sdX/device/delete

Notice the host1 in the returned line above. That’s the controller that needs rescanned.
Trigger rescan:

# echo "- - -" > /sys/class/scsi_host/host1/scan

This should do it. If the device is still alive, it should return to working condition.

You can monitor dmesg for status information.