[CentOS] mariadb server memory usage

[hw]

marcos valentine wrote:
>> This free memory can go away in less than a second
>
> It's depends of many things. But you need to pay attention on this variables
>
> https://mariadb.com/kb/en/library/mariadb-memory-allocation/

Thanks, that´s an interesting page.

It tells you to turn off hyperthreading.  At some other place on the
mariadb website, I´ve been reading it´s generally a good idea to
leave it turned on for mariadb.

Now which is true?

> In my db servers i use nagios to monitor when "free" and "available" ram is
> less than 80% warning state and less than 5% critical.

Hmm, nagios, yes, I should look into that.

>> so I figured why not use as much as possible --- just not too much, and
> this is borderline.
>
> You can use the rule always 80% used for safe. But 20% of 46GB could be too
> much ram wasted.

It would be a pity to waste it.  I think 128GB would be ideal, and the
machine might even get that once I get to shuffle the RAM sticks
around between different machines.  I still wouldn´t want to waste any.