Usage: sg_bg_ctl  [--ctl=CTL] [--help] [--time=TN] [--verbose] [--version]
                  DEVICE
  where:
    --ctl=CTL|-c CTL    CTL is background operation control value
                        default: 0 -> don't change background operations
                        1 -> start; 2 -> stop
    --help|-h          print out usage message
    --time=TN|-t TN    TN (units 100 ms) is max time to perform background
                       operations (def: 0 -> no limit)
    --verbose|-v       increase verbosity
    --version|-V       print version string and exit

Performs a SCSI BACKGROUND CONTROL command. It can start or stop
'advanced background operations'. Operations started by this command
(i.e. when ctl=1) are termed as 'host initiated' and allow a resource or
thin provisioned device (disk) to perform garbage collection type operations.
These may degrade performance while they occur. Hence it is best to
perform this action while the computer is not too busy.