I suggest reading some MySQL document about its configuration parameters.

The default value of innodb_buffer_pool_size is only 8M, will it be better to set it 512M or 1G in my.cnf for speed up DB performance?

Thanks for your solution (innodb_file_per_table=1), i will add this in next release of iRedMail.
About Amavisd queries, all are coded in libs/amavisd/*.py (especially log.py and quarantine.py). Let me know if you have any idea to improve it.

I've been experiencing issues with iRedAdmin (and overall system performance) after my amavisd database started to grow.

On my first tests, I found out that iredmail's my.cnf comes with the innodb_file_per_table variable disabled, this leads to a huge performance decrease as in InnoDB, by default, all of the tables are written to one file defined by default at 10MB, with an auto-extend of 8 bytes. Each time it gets to the endpoint, MySQL has to copy the file to another location and add those 8 bytes, before deleting the old one.

To fix this, I've backed up my database (http://sysadminnotebook.blogspot.com.br … store.html), edited /etc/my.cnf, added
innodb_file_per_table=1
Then stopped mysql, backed up /var/lib/mysql, deleted /var/lib/mysql/*, ran mysql_install_db, started mysql, restored my backup, restarted mysql.

My system load is now much lower, but logging in to iRedAdmin-Pro still takes considerable time. I've disabled the amavis database option on settings.ini, and it's ok now, but listing sent/received emails is a nice feature for my customers. Can you describe queries you're performing ? Those could be optimized (or maybe cached), I may take a look at those if you could point out where they are in code.

Thanks!