[mythtv] New idea for storing recordings to disks

Terry Barnaby terry1 at beam.ltd.uk
Mon Jul 4 11:37:17 EDT 2005


Thomas M. Pluth wrote:
> Comments?
> 
>   How about something like this ;
> 
> 1) Define a single location for recordings.  This should be a high speed
> disk right on your master backend and have enough available space to handle
> your typical daily recording load.
> 
> 2)  Define a group of long term storage locations.  These could be on a file
> server, a large capacity USB or firewire drive, or wherever you happen to
> have available space.   Each of these drives would be a separate mount point
> (/myth/recordings1, /myth/recordings2, etc.).
> 
> 3)  Modify mythcommflag to optionally move the file from the primary
> recording location to the long term storage location as it's performing
> commercial scanning.
> 
>   I would implement this such that each long term storage location could be
> assigned a priority of 1-n.  In the recording options, add a storage
> priority for each recording schedule that will control whether it gets moved
> or not and to where. Specifying a priority of 0 would leave the recording on
> the original location, specifying 1-n would cause mythcommflag to move it to
> the appropriate long term storage locations.   It should be possible to
> define multiple locations with the same priority, as well.
> 
> An example ;
> 
> Drive      Priority  Drive type    Description
> -----                ------------  ----------------------------------------
> 
> /dev/sda      0      146GB 15K     Contains O/S, swap, live TV ringbuffers,
>                      U320 SCSI     primary recording location 
> 
> /dev/hda      4      80GB 7200     An old 80GB drive you had laying around
>                      EIDE          for your children's Barney recordings
> 
> /dev/sdb      1      300GB SATA    Your important shows
> 
> /dev/sdc      1      300GB SATA    Your important shows
> 
> /dev/sdd      2      200GB USB     Your less important shows
> 
> 
>  This implementation would let you use your highest performance storage
> devices where they'd do you the most good and would allow you to use lower
> performance devices (USB, Firewaire, etc.) for recordings without impacting
> the ability of the backend to keep up with I/O activity during heavy
> recording periods.  You would also be able to add storage on the fly by
> plugging in another USB or Firewire drive at any time and adding it to an
> existing priority.
> 
>   Look Mom, no LVM, no RAID, no separate file server!
> 

Sounds good to me.
It would be good to have an option so that all recordings marked as
"no-expire" get moved off to a particular "priority" set of disks.
This would make it work simply and very well without much user
configuration.
Also this should work whether or not commercial flagging is employed.
Actually should you rename "priority" to "diskGroup" ?

Another useful feature would be to stop MythTv accessing the other
disks when the "watch recordings" screen is displayed. At the moment
Myth appears to startup all of my powered down disks when the user
opens the "watch recordings" screen.
Also where would all of MythWebs "*.png" files be stored ?
I would prefer this on the master disk or at a separate location.

Cheers


Terry



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