hdparm
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hdparm is a command line utility to set and view hardware parameters of hard disk drives. It can also be used as a simple benchmarking tool.
Installation
Install the hdparm package. For use with SCSI devices, install the sdparm package.
Usage
Disk info
To get information about hard disks, run the following:
# hdparm -I /dev/sda
Benchmarking
See Benchmarking/Data storage devices.
Power management configuration
Modern hard drives support numerous power management features, the most common ones are summarized in the following table. See hdparm(8)
for the complete list.
Parameter | Description |
---|---|
-B |
Set the Advanced Power Management feature. Possible values are between 1 and 255, low values mean more aggressive power management and higher values mean better performance. Values from 1 to 127 permit spin-down, whereas values from 128 to 254 do not. A value of 255 completely disables the feature. |
-S |
Set the standby (spindown) timeout for the drive. The timeout specifies how long to wait in idle (with no disk activity) before turning off the motor to save power. The value of 0 disables spindown, the values from 1 to 240 specify multiples of 5 seconds and values from 241 to 251 specify multiples of 30 minutes. |
-M |
Set the Automatic Acoustic Management feature. Most modern hard disk drives have the ability to speed down the head movements to reduce their noise output. The possible value depends on the disk, some disks may not support this feature. |
To query current value, pass the parameter without a value. For example:
# hdparm -B /dev/sda
To apply different value, for example set APM to 127:
# hdparm -B 127 /dev/sda
Tips and tricks
Querying the status of the disk without waking it up
Invoking hdparm with the query option is known to wake-up some drives. Instead, consider smartctl
provided by smartmontools to query the device which will not wake up a sleeping disk.
Example:
# smartctl -i -n standby /dev/sda smartctl 6.5 2016-05-07 r4318 [x86_64-linux-4.10.13-1-ARCH] (local build) Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org Device is in STANDBY mode, exit(2)
Working with unsupported hardware
Some drives, particularly external ones, do not support spin down via hdparm. A diagnostic error message similar to the following is a good clue this is the case:
# hdparm -S 240 /dev/sda /dev/sda: setting standby to 240 (20 minutes) HDIO_DRIVE_CMD(setidle) failed: Invalid argument
Such drives can be spun down using hd-idle which ships with a systemd service. One need only edit /etc/conf.d/hd-idle
and edit the "HD_IDLE_OPTS" line followed by starting and enabling hd-idle.service
:
Example using a 30 min idle time for sda:
HD_IDLE_OPTS="-i 0 -a sda -i 1800"
Persistent configuration using udev rule
To make the setting persistent, adapt the following udev rule:
/etc/udev/rules.d/50-hdparm.rules
ACTION=="add", SUBSYSTEM=="block", KERNEL=="sda", RUN+="/usr/bin/hdparm -B 254 -S 0 /dev/sda"
Systems with multiple hard drives, can make the rule more flexible. For example, to apply power-saving settings for all external drives (assuming there is only one internal drive, /dev/sda
):
/etc/udev/rules.d/50-hdparm.rules
ACTION=="add|change", KERNEL=="sd[b-z]", ATTR{queue/rotational}=="1", RUN+="/usr/bin/hdparm -B 127 -S 12 /dev/%k"
Putting a drive to sleep directly after boot
A device which is rarely needed can be put to sleep directly at the end of the boot process. This does not work with the above udev rule because it happens too early. In order to issue the command when the boot is completed, just create a systemd service.
/etc/systemd/system/hdparm.service
[Unit] Description=hdparm sleep [Service] Type=oneshot ExecStart=/usr/bin/hdparm -q -S 120 -y /dev/sdb [Install] WantedBy=multi-user.target
Then enable it.
Troubleshooting
APM level reset after suspend
The APM level may get reset after a suspend requiring it to be re-executed after each resume. This can be automated with the following systemd unit (adapted from a forum thread):
/etc/systemd/system/apm.service
[Unit] Description=Local system resume actions After=suspend.target hybrid-sleep.target hibernate.target [Service] Type=simple ExecStart=/usr/bin/hdparm -B 254 /dev/sda [Install] WantedBy=sleep.target
Alternatively, create a hook in /usr/lib/systemd/system-sleep.