[wellylug] Testing hard disks

[Ewen McNeill]

In message <20030917054042.GA30107 at paradise.net.nz>, Volker Kuhlmann writes:
>A 15G disk I have is throwing I/O errors on the 5G partition, all the
>rest is fine. I nulled out that partition with dd and then ran badblocks
>-w, which found no errors. When I went to install the system on that
>partition, the I/O errors in syslog keep scrolling past.

The only time I've had I/O errors with disks that pass badblocks are:
- when the file system is really messed up (usually from previous
  corruptions due to hardware failures, so that it points at blocks that
  don't exist); or

- when there's some sort of DMA issue.

The former is fixable by newfs'ing the partition again (preferably after
copying what data you can off it, if the data matters); the latter can
be worked around by turning off DMA.

Without seeing the I/O errors you mention it's hard to be sure what's
going on, but I'd expect that badblocks -w, which simply writes to each
block, flushes the cache, and reads it back in again (4 times, with 4
different patterns) would trigger the same issues as an I/O install,
since it's going through the same hardware calls.

Ewen