[mythtv-users] mythbackend hanging with busy disk

[Jeffrey Ratcliffe]

On 7 April 2016 at 04:35, Stephen Worthington <stephen_agent at jsw.gen.nz> wrote:
> 1) Disk thrashing - where there are two or more sources of ultra-heavy
> disk activity, each causing so much activity that the other can not
> make any progress.  If you have mythcommflag running on multiple
> recordings (started at the end of the recording) and a database backup
> happening at the same time, you will likely get disk thrashing (unless
> it is an SSD).

I have mythcommflag turned off. Just checked. Which is a shame,
because otherwise the symptoms fit.

> 2) Disk full.  This is usually caused by log files filling up the
> disk, due to some problem that does not properly control the resulting
> log messages, or say a DDNS attack on a router causing massive traffic
> from it.  But I have also had a MythTV backup to the same disk as the
> database causing it to go full.  My database is always growing and is
> now huge, so the backup process, which creates an ASCII SQL dump of
> the database first, then compresses it with gzip, was overflowing the
> disk, either in the first stage of creating the dump, or when it
> needed to create new file to compress that dump into.  So check where
> your backups are going and the relative size of your database versus
> the free space.  The database is normally in
> /var/lib/mysql/mythconverg and backups default to going to
> /var/lib/mythtv/db_backups.

Not having anywhere off-disk to back up the database, it doesn't. I
should probably rethink this, but at least this isn't responsible for
the current problem.

Thanks

Jeff