====== SATA/SCSI restart ======

Look at dmesg to know which scsi bus is the one that corresponds to the sata channel.

  scsi5 : ahci

Then execute: 

  echo "0 0 0" > /sys/class/scsi_host/host5/scan

To disconnect a sata disk first umount all filesystems and then do:

  echo 1 > /sys/block/sda/device/delete