External disk won't spindown

I also tested it recently and this bug made really made it through to Karmic as well. It's a bit annoying, but obiviously nobody found a solution for that issue up to now.

This doesn't occur only with sdparm but also sg_start from sg3-utils. My LaCie external HD has the same issue both on a Karmic desktop and a Jaunty server.

Problem seems to be related to udev as the copying of a modified udev rules file to /etc/udev/rules.d temporarily while running the commands as suggested in #117713 seems to work although seems a very unreliable solution. https://bugs.launchpad.net/ubuntu/+source/hdparm/+bug/388506 also seems like a somewhat similar issue that was affecting hdparm.

I did some further investigation. This is *exactly* the same issue as with hdparm. sg_start and sdparm both open the device file in read-write (O_RDWR) mode even though they only need to do it on read-only in order to do ioctls. Ubuntu's udev configuration watches the device files for being closed by a program that had them in open in O_RDWR mode and runs a helper which inspects the disk to add more information about the for udev. This triggers the disk to spin up right after it had been sent the command to spin down.

The solution is to change sg3-utils & sdparm to open on read only as they should have done to begin with. I tried it by compiling a version of sg_start with that modification and it worked as expected. It's hard to believe that this wouldn't have been done by any distribution after all this time.

Oh well, spoke a little too soon - http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=522859 seems to indicate *some* scsi commands do indeed, or have at some point required read-write. In any case that does not seem to be the case for sdparm -C stop.

>> ..seems like a somewhat similar issue that was affecting hdparm.

Ubuntu Lucid Lynx includes a relatively recent version of the sg3_utils package (1.28) that solves the problem and successfully suspends my external USB drive, at least for my configuration. The included sdparm is old (1.02) and it doesn't work.

I spoke a little too soon too. It seems that I can spin down my disk by doing sudo sg_start 0 /dev/sdb but only if the drive is mounted. This is already mentioned in bug #117713 by JoeZ251 in comment #45 (https://bugs.launchpad.net/ubuntu/+bug/117713/comments/45).

I have figured out that if you use the sdparm command on a sg device
the disk will spin down properly. Use sg_map to find out your disk
mapping. You need to have sg3 utils installed.

sdparm -C stop /dev/sg1

On 9/18/10, 666f6f <email address hidden> wrote:
> I spoke a little too soon too. It seems that I can spin down my disk by
> doing sudo sg_start 0 /dev/sdb but only if the drive is mounted. This is
> already mentioned in bug #117713 by JoeZ251 in comment #45
> (https://bugs.launchpad.net/ubuntu/+bug/117713/comments/45).
>
> --
> External disk won't spindown
> https://bugs.launchpad.net/bugs/444818
> You received this bug notification because you are a direct subscriber
> of the bug.
>

Cpp, you are the master of the universe.

Status changed to 'Confirmed' because the bug affects multiple users.

As of version 1.07-1, sdparm includes --readonly option, which can be used along --command=stop to spin down the disk. This fixes this bug.