[mythtv] mysqld and mythbackend dying

[Bruce Markey]

Merle Reine wrote:
> I installed the latest cvs and once I start mysql and then mythbackend, 
> I run: top
> to check the processes.  Mythbackend takes up 87% of the CPU and 78% of 
> the memory  and eventually crashes and kills mysqld.  Has anyone seen 
> this or have an explanation?  I can start mysql and run mythepg, 
> mythweb, mythmusic, etc but not mythbackend.
> 
> I have a 1.4 ghz AMD with 256 meg ram and open BSD.
> 
> Any help would be appreciated.

Hi, Merle. The problem is that you've run out of swap space.

When there is no more room to page out, some programs die
unexpectedly. MythTV is kind of a memory hog right now so
this may contribute to behavior that you would not otherwise
see.

If you run "top" you may see on the "Swap:" line that "free"
is a small fraction of "total". Note, do not worry about
"Mem: ... free" as memory uses the 'bachelor's sink' algorithm
where you don't need to wash a dish until there are no clean
ones left. Mem filling up is normal but swap filling is a
problem.

The amount of swap space should be greater than the amount
of memory. Some old rules of thumb are 1.5x to 2.5x. If
possible, add more swap on a separate spindle from the
current swap area. BSD 'interlaces' swap so you actually
get better performance with two swap partitions, one each
on two different disks. Two swap areas on the same disk
causes the disk heads to thrash and degrade performance.

256 meg memory should be enough but could be borderline.
I would see ongoing page outs when recording with two
tuners and 256MB but one recording was fine. Either way,
a lot of swap space was used.

I hope this helps,

--  bjm