A saída de man hdparm
inclui o seguinte:
-S: Put the drive into idle (low-power) mode, and also set the
standby (spindown) timeout for the drive. This timeout value is used
by the drive to determine how long to wait (with no disk activity)
before turning off the spindle motor to save power. Under such
circumstances, the drive may take as long as 30 seconds to respond to
a subsequent disk access, though most drives are much quicker. The
encoding of the timeout value is somewhat peculiar. A value of zero
means "timeouts are disabled": the device will not automatically enter
standby mode. Values from 1 to 240 specify multiples of 5
seconds, yielding timeouts from 5 seconds to 20 minutes. Values from
241 to 251 specify from 1 to 11 units of 30 minutes, yielding timeouts
from 30 minutes to 5.5 hours. A value of 252 signifies a timeout of
21 minutes. A value of 253 sets a vendor-defined timeout period
between 8 and 12 hours, and the value 254 is reserved. 255 is
interpreted as 21 minutes plus 15 seconds. Note that some older
drives may have very different interpretations of these values.
Sua configuração de 246 significaria, portanto, 6 unidades de 30 minutos (3 horas), embora eu não saiba como o valor para -B
é interpretado quando -S
também é especificado.