hd-idle.1

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.TH HD-IDLE 1 "March 26, 2024"
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.SH NAME
hd-idle \- spin down idle hard disks
.SH SYNOPSIS
.B hd-idle
.RI [ options ]
.P
.SH 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.
.P
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.
.P
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.
.SH OPTIONS
.TP
.B \-a name
Set device name of disks for subsequent idle-time parameters
.B (-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/...)
.TP
.B \-i idle_time
Idle time in seconds for the currently named disk(s) (-a <name>) or for
all disks.
.TP
.B \-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.  
.TP
.B \-t disk
Spin-down the specfified disk immediately and exit.
.TP
.B \-d
Debug mode. This will prevent hd-idle from becoming a daemon and print
debugging info to stdout/stderr
.TP
.B \-f
Foreground mode, no logging to stdout.
.TP
.B \-h
Print usage information.
.SH "DISK SELECTION"
The parameter
.B \-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:
.P
.TP
.B \1)
A
.B \-i
option before the first
.B \-a
option will set the default idle time; hence, compatibility with previous
releases of hd-idle is maintained.
.TP
.B \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.
.SH EXAMPLE
hd-idle -i 0 -a sda -i 300 -a sdb -i 1200
.P
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.
.SH AUTHOR
hd-idle was written by Chistian Mueller <chris@mumac.de>
.PP
This manual page was written by Christian Mueller <chris@mumac.de>,
for the Debian project (and may be used by others).