[mythtv-users] remaining disk space / delete slowly

[Gerald Brandt]

On 2016-07-11 03:15 PM, Joseph Fry wrote:
>
>     Just for clarification, the reason for having delete slowly
>     selected is so recordings are recorded over with a new recording
>     (once) instead of with zeros now and a new recording later
>     (twice). if this is correct I would expect Myth to count deleted
>     recordings (of which I have 55) as available space, as reported on
>     the "watch recordings" screen, which it is not, in my case, and
>     although I know I have more available space than reported - seeing
>     89% full is hard not to react to.
>     Is there any solution, other than a chill pill for this behaviour?
>
>
> As others have stated, the "deleted" recording group is like a recycle 
> bin.
>
> When Mythtv needs space for a recording, it will use any free space 
> first, then it will first delete recordings from the "deleted" 
> recording group, then it will delete "watched" recordings, before 
> finally starting to encroach on your unwatched recordings.  Priority 
> and expiration rules come in to play at all stages of this process.
>
> While it may give you peace of mind to see a bunch of free space on 
> your recording drives when you look at them via the OS... don't be 
> fooled.  You are actually  safer to let mythtv fill your recording 
> drives and manage the deletions on its own.  That said, this assumes 
> that you follow best practices which is that your recording 
> drives/partitions be dedicated to recordings and nothing else.
>
> Here's why it's safer.  If you permanently delete all of your 
> recordings after you watch them (manually, or automatically after X 
> hours/days) you end up with a bunch of free space on your drive.  What 
> happens if you inadvertently (or intentionally) fill that free space 
> with other content... well mythtv will still want space to record in, 
> so it will just delete your unwatched recordings.  if you let mythtv 
> manage the deletions, your drive would always be (almost) full, 
> preventing other users/applications from writing to the drive.  This 
> typically isn't a problem, but it can be; here is the worst I ever 
> read about;
>
> User mounted /var to it's own drive, and had the recordings in 
> /var/mythtv/recordings... seems like a reasonable configuration.  
> However while on vacation for 2 weeks, something got jacked and his 
> server was writing a constant stream of data to /var/log/some.log... 
> IIRC it was 10's of GB/hr.  It wasn't long before his drive had no 
> free space, so every time mythtv wanted to record something, it 
> deleted one of his recordings, but before it got a few minutes in, the 
> drive would be full again so it deleted another... and so on.  
> Needless to say, he came home to find only a handful of recordings 
> left (those he had preserved).
>
> Lets just say, I stopped deleting my recordings from the drive and 
> just let mythtv do it since reading that.  Having the drive full 
> prevents anyone (especially me) from being tempted to dump data there 
> temporarily.
>

What MythTV should do is report disk usage values then, so I can monitor 
if there is enough 'deleted recordings' space for new recordings

used free / free size / deleted size

or do the math and report free as actual free + deleted.

My didk was full (as Myth likes to keep it). I had 12+ hours of 
recording coming up, and I had no idea if I had enough room without 
losing some of my unwatched recordings.

Gerald

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