[mythtv-users] What to do with lots of RAM?

[Simon Hobson]

Jerome Yuzyk <jerome at supernet.ab.ca> wrote:

> My "new" 0.27.4 FE/BE has 4G of RAM, only 1M of which seems to be used, leaving me to wonder what I can do with the rest of it to speed up MythTV as much as possible. Other than running rsyncd to be a backup for my other machines, the box is only going to run MythTV and maybe a browser for Internet content. 
> 
> 
> MySQL tuning is an obvious candidate, and I've already added some MySQL settings from
> https://www.mythtv.org/wiki/Installing_MythTV_on_Fedora#MariaDB_performance
> 
> 	key_buffer = 16M
> 	table_cache = 128
> 	sort_buffer_size = 2M
> 	myisam_sort_buffer_size = 8M
> 	query_cache_size = 16M

Ignore other people's numbers - use mysqltuner.pl.
Note that you'll need to adjust your settings over time as the tables (particularly oldrecorded) get bigger. Read up on what each setting it suggests actually does, and be prepared to take a while as you need to leave the system to run for a while to get valid stats after making changes.

Your aim is to try and get all the tables to stay in ram all the time - that minimises disk access.

Other than this, just let the system use the extra ram for caching. For one thing, it'll help with things like commflagging and trancoding new recordings by allowing more of the new recording to stay in ram.