Constant Flow

Hdparm offers the option to test data throughput with the -t, -T, and --direct parameters. If you notice poor performance of a computer system, the throughput test helps you track the cause of the problem because the tool determines the throughput for the processor, system cache memory, and RAM using the -t and -T parameters. You need to launch the tests several times in succession to obtain a realistic mean value.

If you set the --direct parameter in conjunction with -t, hdparm bypasses the cache and reads data directly from the specified drive. Therefore, this test is well suited to testing the drive performance, depending on the interface used. Poor throughput rates often indicate problems with mass storage media. With conventional hard disk drives, in particular, hdparm helps to improve read rates, and thus throughput values, using many optimization parameters. However, incorrect application of certain options entails a risk of data loss.

Power Tool

The software can also help reduce energy consumption, mainly in the case of hard drives, and thus reduce mechanical wear. For example, in the case of aggressive power management, the -B parameter reduces the number of park operations for the hard disk heads, which also prevents premature spin-down of the hard disk, which, in turn, can reduce energy consumption in many cases because constantly starting up the disk drive requires significantly more energy after a spin-down than continuous operation at idle speed without switching off the drive motors.

The values for power management that follow the -B parameter range between 1 and 255 for most models; the lowest value generally triggers a complete spin-down, whereas the highest value completely disables power management. However, because the individual values vary depending on the hard disk vendor, and partly on the model, several test runs are usually required to achieve the best value.

The --idle-immediate, --idle-unload, and -S parameters can be used in combination to reduce energy requirements and help reduce mechanical wear. With Hitachi hard drives, hdparm uses the -H parameter to read the current operating temperatures; this is useful for older Microdrive hard disks, in particular.

Security

Hdparm also assigns drive passwords on the basis of the ATA standard by using various parameters. The result is that third parties can only access the device in question after authentication. Using the --security-erase and --security-erase-enhanced options, you can securely delete drives so that the deleted data cannot be reconstructed. In the case of most drives, an overview of technical features in the Security section will tell how long the deletion process will take.