[Discuss] Ext4, ugh! Re: Disk recovery utilities - dealing with deleted files

[richb at pioneer.ci.net (Rich Braun)]

It's starting to look to me like the bottom line is this:

  DO *NOT* USE EXT4!

There are a handful of well-documented utilities available for recovering ext3
volumes, and pretty much nothing for ext4.  The ones that claim support for
ext4 give no meaningful debugging output, and rely solely on contents of a
journal that's apparently gone.  My theory is that the act of typing 'umount'
to take the volume offline is likely what zeroes out an ext4 journal, but
that's only a guess and I haven't been able to really figure out very much.

I'm having to resort to backups, which of course for a terabyte volume are
done far less often than the others.  (Fortunately, I didn't use CrashPlan for
those, so I can count on their integrity. ;-/)  I lost a number of months of
recordings, alas my coverage of the 2012 election cycle is vanished in a puff
of filesystem shuffling.  I know the footage is /there/, I just don't have any
way to extract it in a playable way.  Ugh.  Now I have about 15 terabytes of
ext4 volumes that I need to rebuild as ext3 or as whatever else y'all
recommend (such recommendations /have/ to come with a robust undelete!).

Again, did I mention that ext4 is not enough of an improvement over ext3 to
ever use it again!?!

-rich