Hot-swap SATA disks in FreeBSD

If you ever need to hot-swap a disk on a FreeBSD box, atacontrol(8) is your friend. Swap the disk, then use atacontrol list to retrieve the list of ATA channels on the system.

root@neutron:~-> atacontrol list
ATA channel 0:
    Master: acd0  ATA/ATAPI revision 5
    Slave:       no device present
ATA channel 2:
    Master:  ad4  SATA revision 2.x
    Slave:       no device present
ATA channel 3:
    Master:  ad6  SATA revision 2.x
    Slave:       no device present
ATA channel 4:
    Master:  ad8  SATA revision 1.x
    Slave:       no device present
ATA channel 5:
    Master:    no device present
    Slave:       no device present

Find the appropriate channel, in this case ata5. Then simply perform a detach/attach operation on the channel and the disk should be found.

root@neutron:~-> atacontrol detach ata5
root@neutron:~-> atacontrol attach ata5
Master: ad10  SATA revision 2.x
Slave:       no device present

This example was done on FreeBSD 8.1-RELEASE.