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Revision as of 10:39, 24 September 2013 by Wombalton (Talk | contribs) (Parking your hard drive: corrected minor mistake in udev rule)

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

Warning: Be careful, it is easy to destroy your hard drive with hdparm!


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


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.

Note: bf is just the name of the output file that dd writes to.

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. That could be automated via a systemd resume@ service file.

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

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