Apparently most (all?) of WD's Green drives have a technology (intelliseek?) that suspends the heads after 8 seconds of inactivity. This is normally not a problem and something you can adjust with hdparm, however this is not possible, at least not with the two drives I have.
Changing APM (Advanced Power Management) is apparently not possible, this is the error i get when trying to change it on my WDC WD20EARX:
$ sudo hdparm -B 255 /dev/sdb /dev/sdb: setting Advanced Power Management level to disabled HDIO_DRIVE_CMD failed: Input/output error APM_level = not supported
When I try to change the timeout value, hdparm reports no errors but the loadcyclecount continues to increase, fast.
$ sudo hdparm -S 0 /dev/sdb /dev/sdb: setting standby to 0 (off) $ sudo smartctl --all /dev/sdb | grep 193 && sleep 8 && sudo smartctl --all /dev/sdb | grep 193 193 Load_Cycle_Count 0x0032 198 198 000 Old_age Always - 7945 193 Load_Cycle_Count 0x0032 198 198 000 Old_age Always - 7946
Because the LoadCycleCount increases we can assume that smartctl wakes up the drive, even though we tried turning of the standby function.
I also tried different values for the standby timeout, 0, 251, 240, 253 (vendor-specific) and 255, nothing stopped the LoadCycleCount from increasing.
The problem with this is that the drive is rated for 300k load cycles, which would mean my drives will fail in under two years (my drive have been powered on for 360 hours, that is 22 load cycles per hour).
Apparently there are tools from WD that might help, however I have not yet tried them. This link describes some ways to fix the issue, but they did not work, as you can see above, it does also link to another page which in turn links to two tools which I might give a try to see what happens.
Here is some links that take up the subject, I have not tried anything posted on any of the links, however that's my intention.