Hi folks,
I have a question about APM settings and Standby and how they are related? Specifically when using hdparm to control the parameters and behavior on drives, according Archlinux Wiki: hdparm - ArchWiki
hdparm -B sets the APM value between 0-255, and that "Values from 1 to 127 permit spin-down, whereas values from 128 to 254 do not"
hdparm -S sets the spin down timer and above 240 increases the timer in 30 min increments.
My interpretation of hdparm -B is that if APM value is above 127, that will essentially disable the timer value set by hdparm -S. I just did some testing and that does not appear to be the case, even setting the APM value using hdparm -B 190 on my Toshiba drives with a hdparm -S 240 still allows the drives to under spin-down/standby state, I can tell by the power consumption of the server.
So if that's the case, what does it really mean when the manual say APM "values from 128-254 do not permit spin-down"?
I have a question about APM settings and Standby and how they are related? Specifically when using hdparm to control the parameters and behavior on drives, according Archlinux Wiki: hdparm - ArchWiki
hdparm -B sets the APM value between 0-255, and that "Values from 1 to 127 permit spin-down, whereas values from 128 to 254 do not"
hdparm -S sets the spin down timer and above 240 increases the timer in 30 min increments.
My interpretation of hdparm -B is that if APM value is above 127, that will essentially disable the timer value set by hdparm -S. I just did some testing and that does not appear to be the case, even setting the APM value using hdparm -B 190 on my Toshiba drives with a hdparm -S 240 still allows the drives to under spin-down/standby state, I can tell by the power consumption of the server.
So if that's the case, what does it really mean when the manual say APM "values from 128-254 do not permit spin-down"?