disk spin down <summary>

[Pierre Turlais]

Peter S Galbraith writes:
 > 
 > [Bottom line: Can scsi-idle be used with swap?]
 > 
 > I wrote:
 > 
 > > I apologize if this isn't the proper forum.  I don't know if this
 > > is handled by the SCSI driver or not.  I use Linux pre-patch-2.0.31-3.
 > > 
 > > I have a spare disk I use exclusively for nightly backups, and 
 > > optionally seldom used swap.  I'd like to spin down the disk when not 
 > > in use (and unmounted) because of it's whinning sound.  
 > 
 > Pierre Turlais told me about scsi-idle:
 > 
 > Title:          scsi-idle - Turn off SCSI disks when idle (Take 2)
 > Description:    A small kernel patch which spins down SCSI-disks after a 
 >                 period of inactivity. 
 >                 scsi-idle can probably be considered to be BETA software now, 
 >                 it works for me and half dozen other people, but YMMV.
 > 
 > I patched the Linux kernel and tried the program when no partitions were
 > mounted.  It worked but I got the following messages:
 > 
 >  kernel: SCSI host 0 channel 0 reset (pid 4623) timed out - trying harder
 >  kernel: SCSI bus is being reset for host 0 channel 0.
 >  kernel: (scsi0:-1:0) Reset device, active_scb 1
 >  kernel: scsi0: (targ -1/chan A) matching scb to (targ 1/chan A)
 >  last message repeated 2 times
 >  kernel: scsi0: Resetting current channel A
 >  kernel: scsi0: Channel reset, sequencer restarted
 >  kernel: (scsi0:1:0) Aborting scb 1
 > 
 > I assume all this is normal.
 > 
 > Then I enabled a swap partition on the spun-down SCSI disk and it spun-up
 > again to turn on swap.  I told scsi-idle to spin down the disk after 5
 > minutes of inactivity.  It spun down after 5 minute as I never swap much.
 > 
 > And I got these messages:
 > 
 >  kernel: scsi : aborting command due to timeout : pid 5539, scsi0, channel 0, id 1, lun 0 Start/Stop Unit 00 00 00 00 00 
    ..........
 >  last message repeated 2 times
 >  kernel: scsi0: Resetting current channel A
 >  kernel: scsi0: Channel reset, sequencer restarted
 >  kernel: (scsi0:1:0) Aborting scb 0

 I can easily lock my computer if I execute a program which resides on
the idle disk. I was also able to lock it once with a file on this
disk mmaped. If I use it for storage with mv/cp, no problem.
For me, you better avoid to use it for swap or use something like an
automounter, whick will also manages the idle on unmout.

tchao

Pierre TURLAIS