Full Circle

LINUX LAB
Written by Charles McColm
Testing & Troubleshooting Hard Drives
Several years ago, I bought a
number of new components
from an online retailer only to
discover some of the equipment
was bad. I figured since the
hardware was new and in the
sealed packing when I bought it, I
wouldn’t have any problems.
Whether you’re building a new
system or refurbishing an old one,
it’s always a good idea to test your
hardware. Since hard drives are
most people’s permanent storage,
having a healthy hard drive is
almost as important as good
steady power to the computer.
In the past, our refurbishing
project has used a few methods to
detect bad drives: The first method
was just listening to the drive. If
the drive sounded whiny (or had
the notorious click of death), we
either wiped the drive with DBAN
(Darik’s Boot and Nuke -
http://www.dban.org/), or took
apart the drive and sent it to our
end-of-life processor. The second
way we knew a drive was bad was
if it failed DBAN. This method
wasn’t foolproof because drives
with bad sectors could fully DBAN.
Sometimes our volunteers would
forget to hook up the data or
power cable, so the drive wouldn’t
be detected and would also fail
DBAN. The last method was to
examine the hard drive using
Gsmartcontrol. Gsmartcontrol is
great because it can instantly
detect certain kinds of SMART
(Self-Monitoring, Analysis and
Reporting Technology) errors.
Unfortunately, SMART isn’t
perfect. Wikipedia has an excellent
article covering SMART that
mentions that in one study more
than 50% of drives that failed did
so without triggering one of the
main SMART failure indicators.
To augment our SMART testing,
we’re starting to use WHDD, a tool
ported to Ubuntu by Eugene San.
WHDD bills itself as a hard disk
drive diagnostic and recovery tool.
What we like about WHDD is that
it can run a disk read surface scan
fairly rapidly. Smartmontools and
Gsmartcontrol can be used to run a
short (approximately 2 minute)
electrical and mechanical test, but
the short test covers only a small
part of the drive. Both tools can
also be used to run a
Long/Extended test which scans
the entire surface of the drive, but
the Long test is as the name
describes, long. Even small (80GB)
hard drives can take several hours
to scan.
This is where WHDD comes in
handy. WHDD can run a complete
surface READ scan on an 80GB
hard drive in under 22 minutes (1 7
minutes on one of our Seagate
drives). Our larger 3TB drive (which
was completely full of data)
finished in 245 minutes. Below is a
small sampling of the time/size
full circle magazine #1 08 40 contents ^