[mythtv-users] Partition resizing gone wrong - All storage groups gone (on the same partition)

[Stephen Worthington]

On Wed, 11 Sep 2013 14:20:24 -0400, you wrote:

>Stupidly, I resized my partitions today with a third party tool that had
>previously worked before.  When I was done, I rebooted and dropped into
>maintenance mode (lovely).  After letting fsck.ext4 spit out numbers for
>two hours on my terminal, I knew that things were probably bad, and that I
>didn't value the recordings that much anyway, since I view them and delete
>them.  I decided to put the partition down like Old Yeller.
>
>So, now I'm back up, and I ran find_orphans.py, and I have an empty set in
>mythconverg.recorded (sniff).  There seem to be ghosts in other places.
>I'm not a database tinkerer when I don't know the schema.  Is the system
>good to go?  I have this morning's database backup just in case I need it.
>Recordings are scheduled as early as this evening.
>
>I'm not sure if I'm reading this correctly, but it looks like those old
>recordings were rescheduled from reading the mythbackend log.  Is this what
>happens when one runs find_orphans.py?
>
>What should I look at to make sure I'm out of the woods?
>
>In the future, in case I decide to do something like this again, would
>gparted work on a more reliable basis?  I'm kicking myself that I didn't
>try that first.  I did a backup of my system partitions yesterday, so I
>wasn't worried about that, but I don't normally back up the media since I'm
>one of those watch it and get rid of it people, and I don't want to wait
>for all those gigabytes to back up :)
>
>Thanks!
>Jerry

Resizing partitions with data in them is always hazardous - if you
value the data, you need to back it up first.  Which is always a
problem with recordings, as they are usually huge files and need a
huge drive to backup to.

What I would recommend is when creating a recording partition, use a
separate drive and set the partition to use the entire drive, or at
least all remaining space on the drive.  And then never resize it.

If you run out of space, either add another drive, or replace the
existing one with a much bigger one.  In the latter case, you can swap
out the old drive for the new one, then temporarily mount the old
drive on an external drive mount (eSATA or USB 3) and copy all the
data to the new drive.  If you do not have an eSATA or USB 3 port or
external drive mount available, it is actually quite easy to have a
SATA cable and the end of a SATA power cable hanging out the back of
your MythTV box.  There is usually a spare slot you can take the slot
cover off to allow cables out of the box.  SATA is normally hot
swappable on almost all motherboards now, so you can swap drives on
the SATA cable just the same way as in an eSATA drive mount.

If you really do need to resize a partition, then the best resizing
tools will always force an fsck on the partition before resizing it.
The most common cause of problems with resizing is doing it on a
partition that has even a small problem somewhere in the filesystem.
Also, some filesystems are much better at being resized than others as
they have actually been designed to support it.  I prefer JFS for my
recording partitions, and it is designed like that, at least for
expanding the partition size.