[mythtv-users] my experience with myth on a solid state drive

[Steven Adeff]

On Fri, Jan 6, 2012 at 1:14 PM, Matthew Zimmerman <mzimmerman at gmail.com> wrote:
> On Thu, Jan 5, 2012 at 3:20 PM, Dan Wilga
> <mythtv-users2 at dwilga-linux1.amherst.edu> wrote:
>> 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
>>
> When I did:
> watch -n 1 du -sh /tmp
> mythbackend --resched
>
> I was using 150mb (must have smaller schedules and less history then
> you real buffs!)
>
> So taking Dan's recommendation, I set in my.cnf and restarted mysql.
> tmp_table_size          = 256M
> max_heap_table_size     = 256M
>
> Sure enough, mythbackend --resched temporarily added only 0.4M of disk
> space to /tmp.
>
> Not sure about snappyness as I actually didn't even test the frontend
> yet, and I don't have an SSD, but that's impressive to me!
>
> Great tip Dan and thanks to Ron for finding where much of the
> temporary disk IO is!

I did the same, but had to use more RAM. I'm at work though and can't
test whether this speeds up other mysql requests for any reason
either.

I'm wondering now though, from what Jay said earlier, what other
memory usage parameters could be better tweaked, and how, for those of
us with enough ram to do so? I know there are recommended mysql
settings for memory usage that get thrown around all the time, but it
would be interesting if anyone that has a better understanding of how
mysql works and is being used by MythTV to give a better description
as to how to tweak them for people with "spare ram" to use?


-- 
Steve
http://www.mythtv.org/wiki/User:Steveadeff
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