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

[Mark Perkins]

Just thought I would give a quick update on where I got to with my crashed
hard disk.

Testdisk worked quite well for me (thanks Doug). I had about 1.8TB of
recordings on the drive. On the first pass Testdisk was able to recover 387
of 498 missing recordings including one of two recordings that I really
wanted (most things I really want get watched quickly after recording, the
stuff that sits there for a long time tends to be well down the viewing
order). The recordings were missing their file names and extensions but I
wrote a script that checked the file size and the number of frames and
matched those to the database to get the correct names back (I assumed
everything was mpg because I only had recordings on the drive and I deleted
everything less than a couple hundred MB because the preview png get
regenerated automatically anyway).

After doing a few more passes with Testdisk I got another 62 recordings back
that also appear to be 100% intact (and the second of the two recordings I
really wanted). I also got another 22 recordings where the filesize was
correct but the frame count was off by a small amount so I am assuming there
may be a small amount of corruption in those files, although I have not been
able to pick it yet on the quick once-over I did.

That left about 27 recordings completely toast. Testdisk is still actually
working on the disk trying to read the faulty area's but it is really really
slow at this stage, only getting about a single byte back about every 10hrs
so it's pretty much done (there is about 75MB it is unable to read at last
count which is down from about 100Mb at the start). I might let it run a
little longer but figure at this stage there is nothing to be gained, the
lost recordings are nothing that particularly concern me.

The only other loss was a missed recording when the backend crashed and
wouldn't reboot, other than that I would have gotten away unscathed.

TL:DR - Testdisk did a great job recovering lost files from crashed hard
disk.