[mythtv-users] combined myth/server
travis at tabbal.net
Thu Apr 22 17:31:02 UTC 2010
On Thu, Apr 22, 2010 at 10:48 AM, Daniel Kristjansson
<danielk at cuymedia.net>wrote:
> The fsync calls are intentional. They prevent starvation on reads when
> the OS decides to write out a very large block of disk buffers. The
> default elevator algorithms used by Linux disto's are optimized for
> maximum throughput, not real time response. But if you are watching
> a recording you want to see your video frames at regular intervals
> and don't really care if the operating system can decode more of them
> if it only does so every few seconds (high throughput).
Very interesting. Thanks for the info. I thought I remembered there was a
good reason for it, but I couldn't remember why. :)
> Unless you have a very large number of recorders or a very old hard
> disk, mythbackend performance problems are at heart mysql performance
> problems. First make sure you are not using ext4 for the mysql storage
> (/var), second look for examples of tuned my.cnf files. The defaults
> save memory at the cost of performance at best, and at worst are
> configured for replicated mysql server farms.
Interesting, my current setup uses ext4 on /var. I'll have to consider
changing that as I have had minor performance issues that are obviously
database related in MythVideo. They don't cause a problem, but if I can
speed it up....
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the mythtv-users