Re: Need help salvaging what I can from major disaster

[Kynn Jones <kynnjo@gmail.com>]

OK, post-mortem:

  1. after reviewing everything, the best hypothesis I have is that
the root of the problem was a bug in my backup script: it should have
checked that the backup disk was properly mounted before proceeding
with the back-up; something may have gone wrong with the mounting of
XD after it was reformatted, but this failure went undetected; rsync
just created the target directory under /media in HD.

  2. it looks like photorec can find a fair bit of recoverable data
from the first XD backup, but it's going to be a long slog to sort out
the recovered files (400GB's worth); for most of this I have an older
backup from 5 months ago; so the problem will be to identify the stuff
added since then.

I guess this is what learning Debian in the "school of hard knocks" is
all about...  This one knocked me out cold.

kj


On 3/12/16, Kynn Jones <kynnjo@gmail.com> wrote:
> I realize that my last e-mail included too little information.  Sorry
> about that.  Here are some more relevant details.
>
> It turns out that I backed up the hard disk (HD) to the external drive
> (XD) twice.  The first backup went well, as far as I can tell.  I
> spot-checked individual files, etc.  Everything looked normal.
>
> This first backup would have sufficed, but after I had done it I came
> across the recommendation that a disk of that size (2TB) should be
> formatted for ext4, whereas I had originally formatted it for ext2.  I
> reformatted the disk for ext4 (fdisk + mkfs.ext4), and then repeated
> the backup.  This backup procedure was in the form of a shell script,
> that I had tested repeatedly.  I just re-ran it.  My memory is fuzzy
> on the subsequent details.  Since everything had gone so well up to
> that point, I probably did not check everything as obsessively as I
> had up to that point, but something must have gone very wrong.
>
> At any rate, at the moment, my only hopes are that
>
>   1. something may be recoverable from the first backup in XD;
>   2. something may be recoverable from HD.
>
> The second of these is (I think) less likely, because I changed the
> partition scheme for HD, going from a single partition, to separate
> partitions for /, /var, /tmp, and swap.  In contrast, XD has always
> consisted of a single partition.
>
> Now I'm looking for some data recovery tool (preferably from Debian)
> that either is part of some bootable media, or that I can use from a
> USB stick after first booting from a Debian Live CD.
>
> Any recommendations for these would be appreciated.
>
> Many thanks in advance!
>
> kj
>