[mythtv-users] Mythfilldatabase is REALLY slow.

Gavin Hurlbut gjhurlbu at gmail.com
Sun Oct 9 20:18:30 UTC 2011


On Sun, Oct 9, 2011 at 12:31 PM, Richard Morton
<richard.e.morton at gmail.com>wrote:

> I disagree with your analysis (sorry). It seems that due to safer defaults
> ext4 is slower and returning to ext3 would be risky on power failure. The
> appropriate response I believe is to use performance options (such as those
> that I have implemented and wish confirmation that are safe) to recover the
> performance lost with the additional data integrity measures.
>
> Correct.  The biggest slownesses are due to making the filesystem safer,
and people not using appropriate speedups that are available to them.
 There's no reason to update atime on mysql data files, so why do we insist
on doing so?

Also, as previously mentioned:

wget mysqltuner.pl

Use that script to see where your mysql setup itself may need tweaking
(buffer sizes, etc.)  Remember to let mysql run for at least 24h between
tweaking sessions.  This is especially important if you are using innodb.
 The default settings for innodb are usually HORRIBLE for performance.  It
really made a huge difference on my system.  Basically, you want as much in
memory as possible (without using ALL the system RAM of course).

My database and my recordings both are on ext4 filesystems *with* barriers
turned on, and I have not seen any significant issues as a result.
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