Some hard drive management tips and tools (on Linux)

Remember why this is called a notepad? Well, now is the time. 😉

To run some disk testing:
– quick tests (1 or a few minutes): smartctl -d ata -t short /dev/sda
– long tests (several hours, stops at first error): smartctl -d ata -t long /dev/sda
To read the results of said testings: smartctl -a /dev/sda

NB: usually smartctl is already installed on the distribution, but in case your provider ships a minimalist OS (this is the case of EUserv, for instance), you’ll need to install it yourself: simply run apt-get install smartmontools.

Another testing tool (haven’t really used it yet): badblocks /dev/sda

To reassign a block (although as far as I tested, this doesn’t work on ext4):
dd if=/dev/zero of=/dev/sda1 bs=4096 count=1 seek=3778301
sync
(cf http://www.gra2.com/article.php/20041015232512624 for more boring/tedious details, notably on how to compute the “seek” position)

Apparently, hdparm can be used to write to arbitrary sectors too, cf http://serverfault.com/questions/461203/how-to-use-hdparm-to-fix-a-pending-sector.

Finally a great combo to erase empty space on a partition, although this probably shouldn’t be used on a live machine because it will fill up the partition with a huge, random file, beore overwriting it several times:
dd if=/dev/urandom of=/some/file.name bs=4M
shred -uvz -n 7 /some/file.name
Source for this combo.
Note that /dev/urandom can be very slow on a cheap CPU, in which case it might be wiser to use /dev/zero as a source of data (since the file will be overwritten several times anyway). Check the documentation of shred, it’s interesting and short.