Hot Add: redetect for devices on Bus 0, replace host0 with host0-.. for other. It's harmless to try with all ready working devices.
echo "- - -" > /sys/class/scsi_host/host0/scan
Hot Remove: spin down and disable device. Be careful - it can be Root, or mounted device.
!!! Some SATA devices are not HOT swap. !!!
echo 1 > /sys/block/sda/device/delete