Default MySQL settings?

Default MySQL settings?

I have a CentOS 6.2 64bit server with 32GB RAM, running DirectAdmin, it is used for shared hosting clients. I am running MySQL 5.5.22

I have only added three lines to my.cnf, those are:



However it seems the server has alot of unused RAM:


[root@server ~]# free -m -g
            total      used      free    shared    buffers    cached
Mem:            31        29          2          0          1        23
-/+ buffers/cache:          3        27
Swap:            1          0          1

Here is same output but with more detail:


[root@server ~]# free -m
            total      used      free    shared    buffers    cached
Mem:        32092      29923      2168          0      2015      24370
-/+ buffers/cache:      3537      28554
Swap:        2047          0      2047

1: What confuses me, is what are the defaults settings/values for MySQL when I am not overriding the values in my.cnf?

2: Are the default MySQL values very limited so that I must raise them higher in my.cnf, or is the default MySQL values more generic so that it will continue to use more and more RAM when I get more and more customers on the server?

3: As loong as I have so much free memory, I like MySQL to always use all the RAM it needs for all the sites, without limiting it – is that best achieved without setting any custom my.cnf values (like a almost empty my.cnf file)?

I have searched and read a lot, but mostly all discussion is about optimizing my.cnf file, however I don’t want to do that before I understand how the default MySQL settings is – because I am afraid I would lower the limit then, and I don’t want to lower them, I want my server to generic use as much as needed of available RAM.

Also I am afraid to run automatic test to generate my.cnf values, because my server will continue to get more clients/sites, and therfor MySQL need of resources will change and increase as time goes by …

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