[mythtv-users] recovery of files and filenames from ext4 partition

[Stephen Worthington]

On Tue, 3 Feb 2015 09:54:33 +1030, you wrote:

>Hi all, just looking to see if anyone has any specific advice / pointers for
>me.
>
>Had to do a reboot last night of Mythbackend (Ubuntu 14.04.01). On reboot
>for some reason one of the 2Tb recording drives spat hundreds of SMART
>errors and crashed and the backend didn't restart (Ubuntu didn't boot). It
>took a little while before I realised things weren't coming back (was doing
>this on essentially headless BE) but once I realised 'all is not well' and
>got a monitor on it there was just a screen full of text errors.
>
>Rebooted, and got the standard Ubuntu file system check which I let do it
>its thing (bad idea but too late now) and everything came back up normally -
>except the one recording drive has no files. It is correctly partitioned
>(ext4) but is file-less / directory-less. No backups (it's just TV). Gparted
>is showing the correct % full but there are no files / directories listed.
>
>What are the suggestions for recovering files. The drive is a wreck, SMART
>is showing it is a failure in progress (plus it 'squeals' now) but *for now*
>it is working.
>
>Essentially I have imaged the failed drive to image file on NAS (gddrescue).
>Then tried recovery with foremost but it didn't find anything. Trying now
>with photorec which appears to be working well - except it does not recover
>file names which renders the recordings as useless until filenames are
>manually corrected, not sure I can be bothered with that.
>
>I'm not happy about it but life is like that. I'm certainly not unhappy
>enough to spend the money on backups (it's just TV). Just wondered if there
>were any other steps that others would recommended in this situation. In
>particular - a file recovery program that would recover files + filenames on
>an ext4 partition?
>
>Thanks in advance!

One thing I have found very helpful when I have recovered files
without any names is to use the file sizes to match the names to a
catalog file that also has the sizes.  The mythconverg database stores
the file sizes for recordings in the recorded.filesize field, so this
SQL would give you a list of all the your recording files and the
matching filenames in size order:

select filesize,basename from recorded order by filesize;

If you then do an ls -lS | sort -nk 5 command on your recovered
recordings directory you will get a listing of those files in size
order also to match against the database output.  The two listings
merged can be used to create a script that would rename all the files
to the correct names.  Let me know if you need any help with
automating the process of creating the script.