NAME

       hd-idle - spin down idle hard disks

SYNOPSIS

       hd-idle [options]

DESCRIPTION

       hd-idle is a utility program for spinning down external disks after a period of idle time.
       Since most external IDE disk enclosures don't  support  setting  the  IDE  idle  timer,  a
       program like hd-idle is required to spin down idle disks automatically.

       A  word  of  caution:  hard  disks don't like spinning up too often. Laptop disks are more
       robust in this respect than desktop disks but if you set your disks to spin down  after  a
       few  seconds you may damage the disk over time due to the stress the spin-up causes on the
       spindle motor and bearings. It seems that manufacturers recommend a minimum idle  time  of
       3-5 minutes, the default in hd-idle is 10 minutes.

       One  more  word  of caution: hd-idle will spin down any disk accessible via the SCSI layer
       (USB, IEEE1394, ...) but it will NOT work with real SCSI disks because they won't spin  up
       automatically.  Thus  it's  not  called scsi-idle and I don't recommend using it on a real
       SCSI system unless you have a kernel patch that automatically starts the SCSI disks  after
       receiving  a sense buffer indicating the disk has been stopped. Without such a patch, real
       SCSI disks won't start again and you can as well pull the plug.

OPTIONS

       -a name
              Set device name of disks for subsequent idle-time parameters (-i).  This  parameter
              is  optional  in the sense that there's a default entry for all disks which are not
              named otherwise by  using  this  parameter.  This  can  also  be  a  symlink  (e.g.
              /dev/disk/by-uuid/...)

       -i idle_time
              Idle time in seconds for the currently named disk(s) (-a <name>) or for all disks.

       -l logfile
              Name  of  logfile  (written  only  after a disk has spun up). Please note that this
              option might cause the disk which holds the logfile to spin up just because another
              disk  had  some  activity. This option should not be used on systems with more than
              one disk except for tuning purposes. On single-disk systems, this option should not
              cause any additional spinups.

       -t disk
              Spin-down the specfified disk immediately and exit.

       -d     Debug  mode.  This  will prevent hd-idle from becoming a daemon and print debugging
              info to stdout/stderr

       -h     Print usage information.

DISK SELECTION

       The parameter -a can be used to set a filter on the disk's device name  (omit  /dev/)  for
       subsequent idle-time settings. The default is all disks:

       1)     A  -i  option  before  the  first  -a option will set the default idle time; hence,
              compatibility with previous releases of hd-idle is maintained.

       2)     In order to disable spin-down of disks per default, and then re-enable spin-down on
              selected disks, set the default idle time to 0.

EXAMPLE

       hd-idle -i 0 -a sda -i 300 -a sdb -i 1200

       This  example sets the default idle time to 0 (meaning hd-idle will never try to spin down
       a disk), then sets explicit idle times for disks which have the string "sda" or  "sdb"  in
       their device name.

AUTHOR

       hd-idle was written by Chistian Mueller <chris@mumac.de>

       This manual page was written by Christian Mueller <chris@mumac.de>, for the Debian project
       (and may be used by others).

                                        September 29, 2011                             HD-IDLE(8)