[mythtvnz] All recordings and LiveTV folders deleted on power cut (aka MythTV ate all of my recordings)

[Stephen Worthington]

On Sun, 31 Jul 2011 15:32:04 +1200, you wrote:

>Hello all,
>
>I am using Mythbuntu 11.04 and it has been happily ticking along for
>about six months since the last set of dramas (I've been using MythTV
>for about four years). I have one HDD for the system and videos and
>another for the recordings (and backups of the system drive). I use
>AutoExpire, so I had a full drive of recordings, most of which were deleted.
>
>Today, we plugged something into the USB port and the machine
>rebooted--something that has happened before and I assume is some weird
>short on the MoBo.
>
>When it restarted, everything appeared to be running perfectly, but
>trying to play any recordings gives an error that the recording can't be
>found. Navigating to the folder, none of the recording files are
>there--the folder is completely empty. Bizarrely, the subfolder of the
>recordings partition, containing backups of things on the main drive, is
>still there and fine. FSCK thinks that the partition is fine (though had
>to create the lost + found folder). Playing LiveTV (which stores files
>on the main HDD) didn't work, as MythTV had deleted the "LiveTV" folder.
>All of my videos are (thankfully) fine. Ironically, all that was deleted
>were the things I don't backup...
>
>In fact, everything seems "A-Okay": new recordings record fine,
>everything else on the drive seems accessible etc. I've just lost all of
>my recordings. MythTV database doesn't seem to think anything was deleted.
>
>There is nothing interesting in either the front or backend logs.
>
>There wasn't enough on there that was critical enough for me to try and
>undelete everything and manually associate each recording (most of which
>are deleted and awaiting AutoExpire) with a database record, but this is
>a pretty major screw-up.
>
>Has anyone got any ideas what could possibly have happened??? It's the
>kind of thing that makes the better half lobby for a more commercial
>solution and I would hate for anyone else out there to have the same
>happen to them.
>
>Thanks in advance,
>
>Aaron

As far as I know, MythTV never deletes directories, so it was likely
not MythTV that caused the problem.  It sounds more like a filesystem
problem, where the crash caused damage to the partition which was not
recovered properly.  On reboot, did you see FSCK run and fix the
partitions?  Did it fix anything?  At the very least it should have
had to process the journals of any drives that were active at the time
of the crash, and if that did not happen it could explain the serious
damage you are seeing.  Note that Mythbuntu 11.04 hides fsck running,
but it does tell you that it is doing it in the splash screens.

When I have a crash or power failure, I prefer to reboot to a separate
maintenance partition (or a live CD) and manually run fsck -C -f on
all partitions to make sure there is nothing wrong before I reboot to
a partition that will write to the crashed partitions.

What type of partition are you using for your recordings?  I am using
EXT3 for my system partitions and JFS for my recording partitions and
have never had a problem like this.  EXT4 has been reported as not
being as good in situations where there is a power failure or reset,
so I have avoided it and stuck with EXT3 which has a very good
reputation for recovering from power failures.  JFS similarly responds
very well to crashes.