Difference between revisions of "Hdparm"

Revision as of 13:36, 12 November 2013

hdparm is a performance and benchmarking tool for your hard disk (SATA/IDE).

Installation

hdparm can be installed from the official repositories. For use with SCSI devices, install sdparm.

Usage

Disk info

To get information about your hard disk, run the following:

# hdparm -I /dev/sda

Reading speed MB/s

To measure how many MB/s your hard disk (SATA/IDE) can read, run the following:

# hdparm -t --direct /dev/sda

Writing speed MB/s

To measure how many MB/s your hard disk (SATA/IDE) can write, run the following:

$ sync;time bash -c "(dd if=/dev/zero of=bf bs=8k count=500000; sync)"

Do not forget to Ctrl+c and rm bf after that.

Parking your hard drive

If your hard drive is clicking many times, the kernel is parking the hard drive's actuator arm (what moves the read/write head). This happens often on laptops (2.5" IDE hard drives). If it happens too often, it could damage your hard drive.

This will just park the reading head when you shut down the computer:

# hdparm -B254 /dev/sda

Default value is -B128. An average value could be -B199 if it is parking too often.

To make this persistent, add a udev rule by creating e.g. /etc/udev/rules.d/11-sda-apm-fix.rules:

ACTION=="add", SUBSYSTEM=="block", KERNEL=="sda", RUN+="/usr/bin/hdparm -B 254 /dev/sda"

or if you have more than one hard drive you could make the rule more flexible:

ACTION=="add|change", KERNEL=="[hs]d[a-z]", ATTR{queue/rotational}=="1", RUN+="/usr/bin/hdparm -B 254 /dev/$kernel"

Note that the APM level may get reset after a suspend, so you will probably also have to re-execute the command after each resume. This can be automated with the following systemd unit: (adapter from a forum thread)

[Unit]
Description=Local system resume actions
After=suspend.target
After=hibernate.target
After=hybrid-sleep.target

[Service]
Type=simple
ExecStart=/usr/bin/hdparm -B 254 /dev/sda

[Install]
WantedBy=suspend.target
WantedBy=hibernate.target
WantedBy=hybrid-sleep.target

Or you could create /usr/lib/systemd/system-sleep/hdparm_set: found here

#!/bin/sh
hdparm -B254 /dev/sda

And make it executable:

chmod +x /usr/lib/systemd/system-sleep/hdparm_set

Tips and tricks

KDE => 4.4.4 and hdparm

To stop KDE version 4.4.4 or greater from messing around with your (manually) configured hdparm values, enter the following and you should be done:

# touch /etc/pm/power.d/harddrive