[mythtv-users] Myth autoexpiring brand new shows

Yeechang Lee ylee at pobox.com
Tue Aug 26 09:50:29 UTC 2008


Michael T. Dean <mtdean at thirdcontact.com> says:
> > If you read my original post, I mention that there are hundreds of
> > items on the auto-expire list that precede the recordings in
> > question.  My auto expire is set to only consider age.  My issue
> > is that they are not being expired in this order.
> 
> They sure are.  You're forgetting about the fact that the "hundreds"
> of items on the auto-expire list that precede the recordings in
> question are on other filesystems (where deleting them would be a
> waste, as it would mean hundreds of recordings must be deleted
> before a deletion actually makes space available for the new
> recording).

The last sentence is a non sequitur.

I'm firmly on Jonny B and Enigma's side. Michael, you and Kevin are
both flat-out wrong on this issue. I'm very surprised that Kevin would
miss this, as he is normally very on-target.

> But, in case I'm wrong about your wanting to figure it out for
> yourself, I'll mention that one potential approach for "fixing" this
> issue was provided in this thread and it all comes down to a
> misconfiguration of your system.

The above is, as far as I can tell, completely wrong. There is no
evidence whatsoever that Enigma's storage group is misconfigured.

I noticed the issue Enigma reported months ago, right after moving to
0.21 and creating a single storage group encompassing three
recording directories over two backends: Recordings were being
auto-deleted (sometimes almost immediately after beng recorded) even
when dozens or hundreds of gigabytes of recordings elsewhere within
the storage group should've been deleted first (based on their
priorities or because they were in the Deleted recording group), as
clearly indicated in the AutoExpire List. I never filed a ticket
because, I figured, such an egregious issue would surely be fixed
ASAP, right? After all, the wiki documentation
(<URL:http://www.mythtv.org/wiki/index.php/Storage_Groups>) and the
official documentation it quotes
(<URL:http://www.mythtv.org/docs/mythtv-HOWTO-9.html#storagegroups>
both say that:

    MythTV will balance concurrent recordings across the available
    directories in a Storage Group in order to spread out the file I/O
    load. MythTV will prefer filesystems that are local to the backend
    over filesystems that are remote until the local filesystem has 2
    concurrent recordings active or other equivalent I/O, then the
    next recording will go to the remote filesystem. The balancing
    method is based purely on I/O, Myth does not try to balance out
    disk space unless a filesystem is too low on free disk space in
    which case it will not be used except as a last resort.

I read the above as saying that while MythTV normally chooses which
directory to store a directory in based on a) local over remote and b)
I/O balance, it would use c) free space as the governing criteria if
the directories a) and b) suggested were out of room. As this thread
demonstrates, other people interpreted this paragraph the exact same
way.

I did obliquely bring the issue up in June
(<URL:http://www.gossamer-threads.com/lists/mythtv/users/337981#337981>);
in retrospect I should have pressed the question further. And then
today I read this thread and feel very, very naive.

As Jonny B wrote:
> Shouldn't the storage groups function use the remote filesystem
> BEFORE deleting *ehem* expiring shows on the local filesystems? This
> is just a logical conclusion on my behalf.

[...]

> > Clearly, there are people who want it to work the other way:
> > filesystems to be given an equal weighting regardless of whether
> > they're local or remote.
> 
> That's not specifically what I'm saying. I don't care which
> filesystem it picks first so much as I care that it uses my ENTIRE
> recording group before it starts erasing recordings that I may or
> may not be ready to have erased. If I've ensured that my recording
> group has 1tb free, it shouldn't matter if it's local, remote, or
> both. It shold use that entire (up to whatever limit I've set) group
> before it starts expiring stuff.

Amen and amen.

-- 
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