[mythtvnz] Balancing free space after adding a recording drive

[Stephen Worthington]

On Mon, 30 Jul 2012 07:56:37 +1200, you wrote:

>On Sun, Jul 29, 2012 at 8:00 PM, <stephen_agent at jsw.gen.nz>  wrote:
>> ...I added another 3 Tbyte WD Green drive to my MythTV box
>> ...recording storage group.
>> For MythTV to work best, it needs the
>> free space to be spread around all the drives, so that it can record
>> to as many of them as it needs to when recording many programs at the
>> same time.  MythTV is pretty good at keeping the free space balanced
>> during normal operation, if you use the normal settings.  It is only
>> on adding a drive that this problem occurs.
>
>I've never heard of that...
>
>We had 500 GB, I added a 1 TB as another storage group, and its spread 
>out nicely after a year or so.
>
>Filesystem                    Size  Used Avail Use% Mounted on
>/dev/sdc1                     466G  322G  144G  69% /myth1
>/dev/sdd1                     932G  600G  332G  64% /myth3
>
>Not that I record a lot, and I only keep 10 episodes normally, but still 
>I fail to see why this re-arrangement might be necessary.

If you are sensible and add a new drive when there is still a
reasonable amount of free space, there is probably no need to
rebalance things.  But by the time I normally install a new drive, it
is too late and I have less than 30 Gibytes free on the others.  I may
already have things expiring - ie no free space at all.  So when I
next have 5 or 6 recordings at the same time (at least twice a week,
due to pre- and postroll), I can be getting one or more of the old
drives completely full.  Then with free space on the new drive, all
the recordings will be happening on there rather than mythbackend
expiring space on one of the full drives for some of the recordings,
and I can get sections of recordings getting dropped randomly.  It is
probably not so bad with my new motherboard, as it does not normally
need any extra disk traffic for the commercial skip processing, but I
prefer to avoid getting anywhere close to that situation.