[mythtv-users] rebalance deleted recordings

Simon Hobson linux at thehobsons.co.uk
Thu Mar 20 16:37:17 UTC 2014

Michael T. Dean <mtdean at thirdcontact.com> wrote:

> On 03/20/2014 10:58 AM, Simon Hobson wrote:
>> It is a known problem (in that it's come up here before) that Myth doesn't always "get it right" when disks are full/nearly full.
> No, MythTV only has a problem when the user specifies the /wrong/ Storage Group Disk Scheduler ( http://www.mythtv.org/wiki/Storage_Groups#Storage_Group_Disk_Scheduler ).  If you run MythTV with full disks, you should be fine as long as you don't specify "Balanced Free Space" or "Balanced Percent Free Space" disk schedulers.  (Note, too, that "Balanced Free Space" is the default--because users complained that it wasn't.  So, you need to change this if you plan to run with full disks.

It may only be a problem with certain settings, but that doesn't make it "not a problem". For "doesn't always get it right" you can (as you've pointed out) add "depending on user settings - and the default setting causes this problem".

>> * Statistically, unless you do something odd, then the recordings you delete are going to be spread across the drives. One "odd" thing would be to fill a drive up with old recordings that you don't get round to watching and deleting, but add an extra drive - so you only watch and delete "new" recordings that went onto the new drive.
> Note, too, that as long as you're not using the "Balanced Free Space" or "Balanced Percent Free Space" Storage Group Disk Schedulers, you'll get the same "statistical" balancing you see.
>> To put some numbers on that, when I put a new drive in a few weeks ago, I had about 40-50G of free space on the (then) only 3TB drive. That drive still has 40-50G of space free on it, but the other drive (which I upgraded from a 750 to 3TB) has between 100 and 200G of extra recordings on it**. So Myth is automatically favouring the less full drive,
> Because you told it to...

IIRC I have the combination method set - so yes it should favour the disk with more free space, but not use it exclusively. And that is what I'm seeing.

>>  and my "watch and delete" process is keeping free space up on the fuller drive even though I'm adding to the total quantity of recordings.
> But if you're generally watching only new stuff, then you're only watching from the new/empty/"most free space" drive, so are no longer balancing...

I see what you're saying. That's not the case for me as I'm using the combination option for recording allocation, so my new recordings aren't all going on the new drive.

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