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HDD stands for "hard disk drive", typically where data is stored on computer. As this is a mechanical device, it is one of the more likely devices to fail inside of your computer. For this reason, make SURE you do a backup of any important data you have. If you do think your HDD is dying, or are having issues and would like to check, all major HDD vendors offer a diagnostic boot cd image. This means you should download it, and burn it onto a cd, and boot your computer off it, which will step you through the process of testing your HDD for issues.


Maxtor/Quantum SCSI

Maxtor's MaxBlast 4 Diagnostic software





Western Digital


Secure deletion

If you have shred installed, you can use

# shred -vz -n 50 /dev/hda

assuming /dev/hda is the disk you'd like to wipe. If you don't have shred installed, you can use trusty dd:

# dd if=/dev/random of=/dev/hda

dban is a boot floppy, that is also included on the Ultimate boot cd

Peter Gutmann's paper on secure deletion of data

Testing on Linux

To test read speed on /dev/sda:

$ sudo hdparm -tT /dev/sda

To test write speed on /dev/sda (this assumes it's mounted and contains /tmp, and you have one gigabyte of available space!)

$ dd count=1k bs=1M if=/dev/zero of=/tmp/test.img

Better tests can be obtained using tools written for the purpose.

This is a hack of dd that will report timing/bandwidth information written by Coraid. It can be found at http://support.coraid.com/support/sr/ddt-8.tgz
Sample output:
    [[email protected] /scratch]# ddt -c 10240 -b 1k .
    * warning: total I/O < total ram - throughput reported may not reflect I/O path.
    Writing to ./ddt.29528 ... syncing ... done.
    sleeping 10 seconds ... done.
    Reading from ./ddt.29528 ... done.
    10   MiB  KiB/s    CPU%
    Write    75851     38
    Read    1024000     50
This is a wonderfully detailed program, useful for getting a comprehensive test of your IO system. Details at http://www.iozone.org/ (and much too complicated to describe here!)

Testing on BSD

Test your read speed on disk /dev/ad0:

# diskinfo -c /dev/ad0

You can also try rawio, iozone, or bonnie from the ports tree.