Re: ..fixing ext3 fs going read-only, was : Sendmail or Qmail ? ..
On Sat, 13 Sep 2003 02:01, Rich Puhek wrote:
> Ted will know a lot more about this than I do, but I'd think that if the
> first two superblocks are corrupt, the likelihood of superblock number 3
> or whatever being good is pretty low compared to the odds that the
> drive/parition is shot. Perhaps that's why e2fsck just gives up on the
> extra superblocks? Of course, then why bother including them?
In principle it seems to be always a good idea to have more copies of your
data than the software knows how to deal with automatically. Then if the
software screws up and mangles everything it touches you may still have a
chance to manually do whatever is necessary to save it.
I recall a story about a tape drive that became damaged in a way that made it
destroy every tape put in it. When some data needed to be restored the first
tape didn't work, they tried it in a second drive and it was proven to be
dead. They got a second backup and repeated the same proceedure...
It was only when they were down to their last backup that someone got wise and
used a different tape drive for the first attempt, which resulted in the data
being read without any errors.
In that situation if a tape robot had control then it would certainly have
trashed all copies of the data. I can imagine similar things happening to a
file system with a dieing hard disk.
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