[mythtv-users] Migrating existing recordings to new Storage Groups

Matt skd5aner at gmail.com
Sat Dec 30 03:37:03 UTC 2006

Bruce, first off... thank you (and the others who helped) for
implementing this.  I've been running SVN from about 5 days before
this change went into SVN.  I'm constantly checking the commits and
have been waiting to see some of the bugs worked out, but with the
exception of a very few initial quirks, it looks like people have been
raving that this is rock solid.  I know a lot of people have been
waiting for this, and I'm always thrilled when myth makes a huge leap
forward and implements new functionality for the masses (and for the
better) rather than just tiny bug fixes or very specific functionality
that only affect a few (although I realize those are important for a
reason, just not globally so).  I suppose that's enough praise? :-D

On 12/29/06, Bruce Markey <bjm at lvcm.com> wrote:
> Matt wrote:
> > Hi,
> >
> >   I'm thinking about upgrading the latest SVN so that I can get rid of
> > my LVM and start using the new storage groups feature (Thank you!).
> Outstanding.
> > A couple of quick questions:
> > 1) What's the easiest way to migrate existing recordings from the old
> > recordings directory to the new storage groups method?  nuvexport
> > w/sql?
> "cp" or "mv". This isn't as daunting as you may think. Before,
> myth had one dir path where recorded files were stored. Now
> with Storage Groups, you can list more than one dir where files
> may be found. Simply put the files in a directory or a dir on
> each new disk/partition then list those directory paths in
> mythtv-setup "6. Storage Directories". That it. Myth will
> look for it's recorded files with the matching basename in any
> of those directories.

Anyway, I didn't know that it was smart enough to simply check all the
storage groups for any file name.  This is nice because I don't have
to load up a single storage directory.  Nice thinking!

> > 2) If PROBABLY going to be rebuilding my be/fe anyway, as it's been
> > acting funky lately and I want a fresh start on everything BESIDES
> > myth.  I've got the database backed up.  I can easily get everything
> > up and running I've just never had the issue of trying to keep
> > existing recordings AND try to incorporate them into the new storage
> > groups.
> If you are not changing the hostname or IP address, there should
> be no issues.


> > My current recording directory is spread across two
> > drives on an LVM.  I want to destroy the LVM and create a single
> > partion on each drive.  Any ideas on how to accomplish this?
> I presume that you have space where you can move your files
> temporarily while you re-partition. If your current LVM mount
> is /bigspace/, move the recorded files you need to /tmpspace/
> or space on another host or whatever.
> Re-partition your two big disks each as one big partation. It
> is best to not have swap or any other partitions (especially
> /var !) on the same disk so that recordings can stream without
> the disk heads having to thrash looking for other files. Mount
> each disk on it's own mount point, for example. /video1/ and
> /video2/. I like to make subdirs for my myth files rather than
> using the top level dir so I'd "mkdir /video1/mythtv" and
> "mkdir /video2/mythtv". You could move all your files into one
> of these dirs or half in each or whatever you want.
> Restore you DB, install current SVN, run mythtv-setup then add
> "/video1/mythtv" and "/video2/mythtv" to your "Default" SG.
> mysql> select basename,title from recorded where starttime='20061229163000';
> +-------------------------+---------------+
> | basename                | title         |
> +-------------------------+---------------+
> | 2364_20061229163000.nuv | Reality Remix |
> +-------------------------+---------------+
> If this file is either "/video1/mythtv/2364_20061229163000.nuv"
> or "/video2/mythtv/2364_20061229163000.nuv" myth will find it.

Just to confirm and relieve any fears before taking the "formating"
plunge and starting over... can you confirm that this sounds like
it'll work?

1) Running current SVN - pre-storage groups (11673)
2) Backing up all old recordings to external hard drive
3) Backed up Database
4) Re-install OS
5) Implement multiple storage directories (1 partition per drive)
6) Copy original recordings into either/both of the storage directories
7) Import backed up database
8) Install current MythTV SVN
9) Configure new storage group directories

After that, myth will automatically see all my old recordings... correct?

> New recordings can be writen to either dir depending on which
> seems to be the "best" choice at the time. If you have two tuner
> cards, myth will write each recording to it's own disk unless
> there is something else going on. This way, each disk's heads
> can stay positioned to append to the end of each file rather
> than thrashing back and forth between mulitple locations.

Yup, I love this feature.  Which is always why it's probably best to
have a single partition per physical disk for storage groups correct?
Or would it really matter if you have 4 tuners recording at the same
time anyway?  Would 2 partitions or 4 partitions be better or worse or

> --  bjm

Again, thanks for the help everyone!  Glad to be an early adopter of
this.  I'll let you know if I find any oddities.


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