[mythtv-users] my experience with myth on a solid state drive
Dan Wilga
mythtv-users2 at dwilga-linux1.amherst.edu
Thu Jan 5 20:20:29 UTC 2012
While I don't necessarily disagree with you on the other points, I have
a suggestion regarding this one:
On 1/5/12 11:20 AM, Ronald Frazier wrote:
> So what was doing all the writes to /tmp? Several times an hour, myth
> recalculates its schedule. When it does, it uses about 500MB of
> temporary mysql tables. That alone was responsible for over 90% of the
> writes on the SSD. So instead, I created /tmp as a tmpfs partition.
> I've got 2GB of ram, so that gives /tmp up to 1GB to use.
You could also just use this in your my.cnf to achieve the same effect:
tmpdir = /dev/shm
However, in the case of MySQL, it's even faster if you prevent it from
ever using temporary files. You can do this by throwing RAM at it with
these two parameters in my.cnf:
tmp_table_size
max_heap_table_size
The default for the heap is a ridiculously small 16M. In practice, I've
found that MySQL will free up RAM it's not actively using, once it's
done with the temporary, in-RAM tables. For more info, see:
http://dev.mysql.com/doc/refman/5.1/en/internal-temporary-tables.html
--
Dan Wilga "Ook."
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