Re: Need help salvaging what I can from major disaster
Kynn Jones a écrit :
>
> 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
Ext2 can handle 2 TB just fine.
> 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.
Before reading your next post, I also thought that the backup disk was
not properly mounted after being reformatted. There should be some form
of size limit or quota on /media to warn against this kind of common
mistake.
> 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.
Yes, but not for this reason. Creating partitions does very little
modification to a disk.
IMO there are two better reasons :
- There were much fewer overwrites to the XD (only filesystem metadata)
than the HD (complete system installation).
- Files on the XD were written in sequence and not modified, meaning
that they are less fragmented and easier to recover.
> 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.
I would have suggested photorec but you already found out.
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