Disk reliability (Was: Node cloning)

[Trent Piepho]

On Fri, 6 Apr 2001, Josip Loncaric wrote:
> Trent Piepho wrote:
> > 
> > When a drive block goes bad, the drive automatically remaps it to a spare
> > block.  If you find bad blocks on a modern hard disk, something is wrong with
> > your drive.
> 
> I've heard that, and yet 'badblocks' finds problems in 20-30% of our IDE
> drives.  This leads to two possible conclusions:

It's even in the badblocks manpage:

       I had no chance to make real tests of this program since I
       use IDE drives, which remap bad blocks. I only  made  some
       tests on floppies.

> (2) drives are not capable of detecting and remaping all problematic
> blocks

I believe that once the drive runs out of spare sectors, you get bad
blocks.

> Overall, we've had serious uncorrectable problems with over 10% of the
> IDE drives we bought, while an additional 25% have problems we corrected
> using 'e2fsck -c ...'.  Obviously, Linux can do more to bypass problem
> areas than the drive's hardware can.

All this talk of bad blocks has motivated me to run badblocks on all our IDE
drives.  They seem to be fairing pretty well:

Maxtor 90432D2 x4, 90871U2 x1:
5400 RPM, 4.32 GB/8.7 GB
  about 2.5 years old, no problems

WD WD75AA x4:
5400 RPM, 7.5 GB
  about 1 year old, no problems

Maxtor 33073H3 x10:
5,400 RPM, 30.7 GB, made 2000/2001
  about 3 months old, two drives failed shortly after installation, no bad 
  blocks