[mythtv-users] Failing disk and imminent holiday - best move is...?

[Michael T. Dean]

On 08/22/2013 09:49 AM, Rick Lane wrote:
> Hi everyone,
>
> First, thanks to all for their work on Myth. I recently went through 
> some hardware issues which meant my system was down for a week and my 
> wife finally admitted she *couldn't* live without it. Result! At least 
> now she'll put up with me at long as mythtv is around :)
>
> On to the matter at hand. My media storage is split across a 1TB 
> system disk and a 2TB mostly-media disk. The 2TB disk is spitting 
> errors out. I don't think it's death is imminent, but having been 
> through this before I know time is of the essence if I want to get 
> everything off it.
>
> On Saturday I leave for a week and am happy that myth would usually do 
> its thing while I'm away without worry, but I want to minimise the 
> potential damage to the wonky disk. Most of my spare space (around 
> 450GB) is actually on the 1TB disk so it's occurred that I could 
> unplug the sick disc while I'm away, but I'm unsure how myth will 
> react to 2/3rds of its local storage disappearing for a week. The tv 
> recording locations are all nested below mount-points so I won't 
> suffer root-drive-strangulation, but will it merrily carry on and just 
> use the space still available or is there any other gotchyas that I 
> haven't thought of?

No problems as long as:

a) You properly set up Storage Groups such that the only directories in 
your SGs are subdirectories within the file system of the 2TB (i.e. you 
did not put the mount point directory/root of the file system into an 
SG).  If you put the mount point directory into the SG, then that 
directory will exist even when the file system is not mounted, so MythTV 
will write to the mount point directory on the parent file system and 
create a mess.
b) You set MythTV to use the Combination or Balanced I/O--not Balanced 
Free Space or Balanced Percent Free Space--Storage Group Disk 
Scheduler.  There's a bug where MythTV will attempt (and fail) to use a 
non-existent directory if you're using a Balanced *Free Space Storage 
Group Disk Scheduler.

If this doesn't describe your current setup, you can fix a) by simply 
shutting down all MythTV applications, then going into mythtv-setup and 
changing the directory list for the SGs to add a subdirectory in the 
listing.  Then, at some point before you want to make the files 
accessible to MythTV, again, use normal file system tools to create a 
new directory on the mounted file system and move the recordings (which 
should only rewrite file system metadata, not actual files, so should be 
very quick and be very little impact on the failing drive).  Then again, 
since you're likely going to replace the disk, you can skip this step 
and just make the files available by moving them to the proper location 
on the new disk.

To fix b), simply change the SG Disk Scheduler in mythtv-setup.  Make 
sure you do both of these things before you leave.

The only effect is you won't be able to play back/access existing 
recordings on the unmounted file system.

Mike