Date: Wed, 16 Sep 1998 21:36:11 -0600 (MDT) From: "Justin T. Gibbs" <gibbs@narnia.plutotech.com> To: Matt Hamilton <matt@clintondale.com> Cc: current@FreeBSD.ORG Subject: Re: SCSI spindowns and CAM Message-ID: <199809170336.VAA05893@narnia.plutotech.com> In-Reply-To: <Pine.BSF.3.96.980916222947.9619B-100000@boris.clintondale.com>
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In article <Pine.BSF.3.96.980916222947.9619B-100000@boris.clintondale.com> you wrote: > Dear All, > I've been meaning to ask this for a while,a nd I wonder if now anything > has changed with CAM being introduced: Is it possible to spin down SCSI > disks when not in use? You could write a trivial daemon to do this. The device statistics code keeps track of the "last busy time" of devices so you can determine how long a device has been idle. You can use the pass-thru driver to go tell the disk to spin down (see camcontrol for an example of how to do this - it has start/stop functionality already, so you could even just use systm to call camcontrol directly). The da driver is smart enough to spin up a device if it has stopped for some reason, so simply queuing I/O to the device should start it back up again. I don't know enough about APM to comment about hooking up to APM events, but anything is possible. > For the record my controller is an onboard AIC7880 and I'm running > -current with CAM (aout) > > Also I get this: > > da0 at ahc0 bus 0 target 1 lun 0 > da0: <IBM DFHSS2W 1717> Fixed Direct Access SCSI2 device > da0: 10.0MB/s transfers (10.0MHz, offset 15), Tagged Queueing Enabled > da0: 2150MB (4404489 512 byte sectors: 255H 63S/T 274C) > da1 at ahc0 bus 0 target 2 lun 0 > da1: <IBM DFHSS2W 4G4G> Fixed Direct Access SCSI2 device > da1: 10.0MB/s transfers (10.0MHz, offset 15), Tagged Queueing Enabled > da1: 2150MB (4404489 512 byte sectors: 255H 63S/T 274C) > > Both the drives are WIDE SCSI-II and I thought they are meant to run at > 20MB/s (I have 20Mb/s set in my Adaptec BIOS)? I haven't had them very > long and so I'm not sure if they were indeed running 20MB/s before CAM was > introduced. There are two ways to achieve 20MB/s. One is to run 20MHz 8bit SCSI. The other is to run 10MHz, 16bit SCSI. It may well be the case that you have ULTRA transfers enabled in your BIOS, but not wide negotiation. The aic7xxx driver takes some care to honor the SCSI-Select options set by the user. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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