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

Bruce Markey bjm at lvcm.com
Sat Dec 30 03:09:10 UTC 2006

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!).


> 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.

> 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.

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.

--  bjm

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