[mythtv-users] coordinating Myth and OS-admin functions
Jerome Yuzyk
jerome at supernet.ab.ca
Sat Sep 13 02:03:13 UTC 2008
[I am using Myth 0.21 on Fedora 7 so if any of this is solved in the latest
release then "D" or whatever.]
After reading the thread about rebuilding seektables I went over to the Wiki
to read about the optimize_mythdb.pl script and it cautions that the backed
should be inactive while the database is being touched. I have been running
it in a cron job for over a year and I haven't had problems but....
Then I got to thinking about all the other tasks I have going on my FE/BE
machine. Especially now since I got a larger drive, which means I am
recording more. I see sometimes errors in my logs around about when my
morning rsync is going so I know there are some collisions happening. I went
looking for some kind of "back-off" mechanism for my machine-maintenance
scripts.
I checked into mythshutdown but either I don't understand how to use it, or it
doesn't work for me. Along my Googling way I came across a script called
idle.sh for KnoppMyth but it didn't do anything for me either. I was a bit
out of stem by then, I admit.
I'm probably not the only one in this position. What do you folks do to keep
the Linux tasks on your machines from bouncing into Myth tasks?
I have several outside-Myth tasks in my crontab:
- the standard Fedora daily/weekly/monthly jobs
. logwatch
. logrotate
. mlocate
. others that are pretty unintrusive
- weekly optimize_mythdb.pl
- weekly rsync system and ~mythtv files (after ZIPping up the database)
The Myth backend has several "sensitive" processes of its own, each one
touching the database:
- recording
- mythcommflag
- mythtranscode
- housekeeping
I spent a non-trivial amount of time, though a little bleary-eyed, reading
around last night and I don't see much discussion of this except as it
pertains to getting the wake-up side of mythshutdown working. There wasn't
any discussion I could find about how to interoperate all the
externally-driven maintenance things with a running backend - there's plenty
of how-to for doing individual tasks, but I guess I was looking for that next
step. Is there nothing to worry about in doing these operations?
Even the 0.22 optimize_mythdb.pl makes no mention of the sensitivity of its
operations nor provides a way to only proceed if it's safe - it just says put
it into crontab to run it once a day. That has to be risky to a backend doing
24/7 recording like mine, No? None of the other scripts in the 0.22 contrib/
seem to acknowledge that there may be a live database operating, doing
transactions.
OK this is long enough. Hope I don't rankle anyone, just some observations and
questions from an ersatz sysadmin trying to make my MythTV more
appliance-like.
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