[mythtv-users] logs from transoding fills disk.

Rod Smith mythtv at rodsbooks.com
Wed Mar 21 14:02:35 UTC 2007

On Wednesday 21 March 2007 08:16, Stefan Thomasson wrote:
> Hi,
> The only times I have had mythtv fail on me is during the following case:
> Sometimes when transoding and removal of commercials, mythtrancode fails
> and get into a loop putting the following in mytbackend.log
> Failed to decode frame.  Position was: 0

I encountered a similar problem once when creating a DVD, but the error 
message was logged to the MythArchive log file. I believe it was a different 
error message, but I don't recall precisely what it was.

> This results in filling up the the parition I have mounted /var/log on
> which results in backend hanging, frontend is not able to access it anyway.

On my combined frontend/backend system, the problem caused MythTV to delete 
all its recordings as the disk filled. I was not in a good mood when I 
discovered this problem!

> - I changed /var/log to a separate partition after after the first incident
> I had with this issue.

I'm planning to redo my partitioning to minimize the risk. I'll have to 
remember that the mythbackend.log file is a potential menace, too.

Given this risk, IMHO log files should NOT go on any partition that holds 
recordings. Unfortunately, this is the way the Ubuntu guide I followed 
specified that things be set up, at least for the MythArchive log file 
(mythbackend.log is on the root partition as the Ubuntu guide specified).

> So the questions are
> - Is the looping a known issue with mythtranscode/mythtv? Solved?
> - Can I prevent the log to fill the disk? Possibillity to disable the log
> (wont stop MT from looping though).

One possibility I've considered to minimize the risk is to implement per-file 
size limits. I *THINK* this is possible under Linux, but I'm not 100% 
positive of this. The trouble is that, depending on how the disk is 
partitioned, this might affect recordings, so the limits would have to be 
awfully high, particularly when recording HD content.

Rod Smith

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