[mythtv-users] Is 4GB RAM overkill for mythtv?

[Chris Isip]

On Thu, Feb 21, 2008 at 8:44 PM, Brad DerManouelian <myth at dermanouelian.com>
wrote:

> On Feb 21, 2008, at 2:10 PM, James Gutshall Jr wrote:
>
> On Thu, Feb 21, 2008 at 3:24 PM, Captain Krypto <captainkrypto at gmail.com>
> wrote:
>
> > ...Besides the usual mythtv functions...
>
>
> Another thought is depending on usage, size, etc, mysql loves memory.  you
> can tweak your my.cnf file to have extra caching, extra allocated memory,
> etc to speed up database queries, etc.  Also, given enough memory, mysql
> will try to run everything from ram.  that is in addition to disk caching
> linux will provide.  however, most of the memory will sit unused on the
> machine, most people tend to use 1-2GB of ram for their higher end
> machines... unless they are not "myth-only" boxes.
> --James
>
>
> I just upgraded my master backend from 512MB (constantly using 200+ MB
> swap) to 2GB RAM which is a bit overkill, but I'd love to make MySQL
> happier. Whenever I am running a mythfilldatabase, my backend refuses to
> make any connections to a frontend until it's done and I believe it's due to
> high MySQL usage. Anyway, my current my.cnf looks like this:
>
> old_passwords=1
> key_buffer = 16M
> table_cache = 128
> sort_buffer_size = 2M
> myisam_sort_buffer_size = 8M
> query_cache_size = 16M
>
> Anyone have recommendations as to what I can set these to or is it more of
> a "raise it, see how it goes, raise it again, see how it goes" type of
> thing?
> The machine runs MySQL, backend (with a PVR-150) and a frontend that's
> only used with a Slingbox when I'm away from home.
>
> -Brad
>
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
>

I installed nagiosgraph on my backend system to measure and graph the amount
of memory being used by programs.  I notice that mysql memory use just
continues to rise, the longer the system is running.   In one instance, I
even saw in my logs that mysql was killed by the kernel out of memory
killer.  I solved this problem by restarting mysql daily when there are no
active recordings or transcoding going on.
Weeklyprevious<https://mymythtv/nagiosgraph/show.cgi?host=localhost&service=RSS%20Mysqld&geom=&rrdopts=&db=RSS&offset=604800#week>/
next<https://mymythtv/nagiosgraph/show.cgi?host=localhost&service=RSS%20Mysqld&geom=&rrdopts=&db=RSS&offset=-604800#week>
[image: Graph]
*RSS*



The dips in the graph correspond to when mysql was restarted.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mythtv.org/pipermail/mythtv-users/attachments/20080222/612fe530/attachment.htm