Re: Fw: SCSI device not spinning up on rw

[Olaf Hering <olh@suse.de>]

 On Mon, Jun 05, Brian King wrote:

> Brian King wrote:
> > Douglas Gilbert wrote:
> >>> I have a SCSI disk, which I want to spin down when the system is not in
> >>> use. I do this by using sdparm, scsi-spin or sg-utils. These tools all
> >>> spin down the SCSI drive by using an IOCTL.
> >>>
> >>> Problem is that the kernel doesn't spin the drive back up. When a
> >>> process requests data from the disk (a simple ls), the kernel responds
> >>> with an I/O error. After some of these errors, reiserfs marks the drive
> >>> read-only.
> > 
> > Setting sdev->allow_restart in struct scsi_device will cause sense
> > key/code/qual of 02/04/02 (not ready, initialization command required)
> > to wake up the scsi error handler and will force scsi core to issue
> > a start unit command to the disk. I added this a while back to handle
> > ipr raid arrays which need a start unit command each time the adapter
> > gets reset. It would be easy enough for sd to use this, either
> > all the time, or only when directed to, or we could add a sysfs attribute
> > to the disk to enable/disable this behavior.
> 
> Please try the attached patch. It adds a sysfs device attribute "allow_restart".
> If you set it to 1, then scsi core will issue a start unit when it sees 02/04/02
> sense data. The attribute is in the same place as the FUA and cache_type
> attributes (eg. /sys/block/sdc/device/scsi_disk:1:1:9:0/allow_restart). 

Is it safe to have this attribute be 1 per default, and let the user
disable it for problematic drives? The IO errors bother me alot...