Sunday, February 18, 2007

Test the cables

I run rdiff-backup to do cheap (space-wise) generational backups on my home directory (my mail, my documents, nothing that is in version control though since that'd be redundant).

Lately, my computer was failing (linux would get corrupted, couldn't ssh in, etc). It seems to have had to do with the nightly backup. After having the data and power cables to my hard drives re-seated, the problem has gone away.

Jerry Pournelle formulated the eponymous "Pournelle's Law" to the effect that a lot of the time, hardware or drive problems are due to bad cables. In this case the cables weren't bad, they just weren't seated right. Possibly they'd jiggled themselves loose over many months in continuous use (my slow work computer is a sort-of server now, so it never goes off anymore).

Of course I back up to a second disk ;-). If the drive really is going bad (despite suddenly getting much more stable the last two nights due to reseating of the data and power cables), then I'll be backed up anyway. I'm glad to see, though, that the drive is probably good (tested with badblocks too, and xfs_check, no errors found).

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