[mythtv-users] Lvm slowdown

Michael T. Dean mtdean at thirdcontact.com
Tue Jan 29 19:41:09 UTC 2008

On 01/29/2008 02:18 PM, Brian Phillips wrote:
> I recently expanded my lvm to a second drive.  I didn't want to wait for
> storage groups and didn't want to run SVN, I'm impatient :(

Especially with the release of 0.21 nearing, you don't need to set up 
LVM to add another drive for MythTV recordings.  Simply add the new 
drive to your system and use myth_archive_job.pl to move recordings from 
your "real" recordings directory and create a symlink in the recordings 
directory referring to the new location of the recording (on the new drive).

Or, if your new drive is bigger than your first, leave the recordings 
where they are, change your recordings directory to refer to the mount 
point used for the new drive, and use a little sh-foo to create symlinks 
on the new drive.  Something like:

for recording in /path/to/recordings/directory/*.{nuv,mpg,png} ; do
  echo $recording
  ln -s $recording /home/mdean/testlinks/`basename $recording`

(Yes, that is proper syntax for the symlink creation--regardless of what 
people may think/what you may have seen.  :)

Since 0.21 (with Storage Groups support) will be released "shortly", 
you'll never have to do anything special with the pre-storage-groups 
Myth version unless you run out of space on the new drive--which is 
unlikely because of the timeframe involved--but if you do, you can  
simply repeat the previous steps with another new drive.

When you install 0.21, you simply remove the symlinks (find 
/path/to/recordings/directory -type l -exec rm {} \; -print) and add the 
directories to one or more storage groups.  And, once you have storage 
groups, you get some nice benefits from having separate filesystems 
(=not having multiple drives/partitions in a multiple-disk (MD, such as 
LVM or RAID) configuration).

Just another option rather than fixing your LVM config...

Mike "no MD in Myth for 2 years+" Dean
(Storage Groups are 14 months old)

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