> Hmm, I see on the man page > > -B > Get/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). > > which seems to say that your value of 128 actually disables spindown. > Thank you for point that out. I did investigate that a little bit further now. First, the simple cases, called Seagate ;-) I have checked 3 different types of Seagate HDDs one labeled Enterprise, one labeled IronWolf, and one labeled Exos. Non of this drives seams to support Advanced power management (APM). I tested the auto spin down beaver of the HDD labeled Enterprise and it works as expected. In my last E-Mail I was a little bit confused because all the Seagate drives often report the state “unknown”. However, now I’m pretty sure that hdparm reports “unknown” when the drive is doing some IO, if the drive is running but doing no IO the state “active/idle” is reported and if the spindle has stoped the state is “standby”. I was not able to check the auto spin down for the IronWolf and Exos until now. I have found 4 HDD types that supports APM for testing. Two HGST HDDs, one with 4 TB and one with 6 TB. A 4 TB WD drive labeled as Red Pro and a 12 TB WD drive labeled as Gold. I did set the APM to 127 for all 4 drives. The two HGST drives and the 4TB WD drive did reach the state “standby”. While the 12 TB WD drive always reported “active/idle” and never reached “standby”. The spin down behaviour of the two HGST drives did not change when I set the APM to 128 on all drives. Also the 12 TB WD still reports “active/idle” permanently. Only the behaviour of the 4 TB WD drive has changed since it seams that it can not reach the state “standby” any more. So from 4 drives only 1 behave as the man page of hdparm suggests. For now my HDD type sample size is too small to draw a final conclusion. But I think it is possible to say that the APM setting is not so straightforward as outlined by the man page of hdparm and you should test this for every drive type. _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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