The new disk in the
homeserver greenblatt was another case of a disk not wanting to go
to sleep after the set period. Some searching found two answers:
spindown, a daemon to
monitor disks for inactivity and spin them down with
sg_start --stop
or
hdparm -y. But the other answer was a better answer:
hdparm standby timeout not working for WD raptors? has as answer:
* I also know of quite a number of drives where hdparm -B settings
override the -S settings, even if you set the -S settings after the
hdparm -B settings. You could try combinations with various values of
hdparm -B, especially 1 and 255.
And the manpage of hdparm has this bit:
-B
Set Advanced Power Management feature, if the drive supports it.
A low value means aggressive power management and a high value
means better performance. Possible settings range from values 1
through 127 (which permit spin-down), and values 128 through 254
(which do not permit spin-down). The highest degree of power
management is attained with a setting of 1, and the highest I/O
performance with a setting of 254. A value of 255 tells hdparm
to disable Advanced Power Management altogether on the drive
(not all drives support disabling it, but most do).
Default on the WD drives is indeed 128, which does not permit spindown
on idle. I changed it to 127, see if that helps. I prefer it if the
drives decide for themselves when to spin down.
Update :
Yes, the changed advanced power management setting helps, now the drive
spins down when not in use.