[lug] Robust storage

[Daniel Webb]

I just noticed I have file corruption in an old mailing list archive (gzip
fails about 1/4 of the way through).  It's not one I care about much,
but it's got me thinking about the issue in general.  I have no idea
when this corruption happened, sometime in the last two years.  Here are
some questions I have for the experts out there:

 * How can I know if files have been corrupted through hardware errors?
   Would Linux software RAID have prevented this?

 * How can I know if files have been corrupted by bugs in the low-level
   block drivers (the filesystem drivers or in my case drbd)?
   Would Linux software RAID have prevented this?  What happens if the
   corruption is cause by the RAID driver?

 * What are some inexpensive solutions to this problem?

I have offline CD backups (every few months) of my important Subversion
repositories, but the thought of manual recovery if there was any
significant corruption gives me the shivers.  I also have nightly
backups to another machine, but if undetected corruption happens on the
main machine, the corruption will just propogate to the backup.