On Tue, Jul 20, 2010 at 03:14:40PM +1000, David Gwynne wrote: > On 20/07/2010, at 2:48 AM, Jan Stary wrote: > > > I wonder whether there is something like atactl(8) that I could use > > to control the power management of these disks - spin them down > > when not used etc, to reduce noise and heat (I have yet to measure > > if it would also mean a nontrivial power saving). > > there is a (very very) slight chance that the chip that translates from scsi > over usb to ata on the actual drive supports the ATA PASSTHRU scsi commands, > which the openbsd kernel will now try. this means you might be able to run > atactl against those disks. > > you will need a -current system to try that with though. > > considering how budget those usb to ata chips are, i wouldnt hold much hope. > > dlg
For what it's worth, I use two different USB disks on my server that are used in a similar fashion to Jan. And, there is always a short delay before using the disks for the first time after a long period of inactivity. So, I think they are sleeping. -ME snippet from dmesg: umass0 at uhub0 port 3 configuration 1 interface 0 "Western Digital External HDD" rev 2.00/1.06 addr 2 umass0: using SCSI over Bulk-Only scsibus2 at umass0: 2 targets, initiator 0 sd1 at scsibus2 targ 1 lun 0: <WD, 5000YS External, 106a> SCSI2 0/direct fixed sd1: 476940MB, 512 bytes/sec, 976773168 sec total uhidev0 at uhub0 port 3 configuration 1 interface 1 "Western Digital External HDD" rev 2.00/1.06 addr 2 uhidev0: iclass 3/0 uhid0 at uhidev0: input=1, output=2, feature=0 umass1 at uhub0 port 4 configuration 1 interface 0 "Western Digital My Book" rev 2.00/1.75 addr 3 umass1: using SCSI over Bulk-Only scsibus3 at umass1: 2 targets, initiator 0 sd2 at scsibus3 targ 1 lun 0: <WD, 10EADS External, 1.75> SCSI2 0/direct fixed sd2: 953869MB, 512 bytes/sec, 1953525168 sec total
