PROBLEM

My I/O performance is stressed and my memory performance is underutilized.

ENVIRONMENT

• On-Premise Server + WebMail Installations: Version 6.0 > Current Version
• Webmail Only Installations: Version 6.0 > Current Version

CAUSE

MySQL has very limited memory allocation for cache use out of the box.

RESOLUTION

You can increase performance dramatically by optimizing the allocation of memory for the cache and buffer.

Atmail uses InnoDB tables for the user authentication & log-files, and if you have a large userbase performance can be dramatically improved by increasing the innodb_buffer_pool_size.

1. Open the my.cnf file in your editor
   

   /etc/my.cnf

2. In the above file, amend the following:
   

   innodb_buffer_pool_size=256M

3. Save the changes and exit

Other tables such as the UserSettings, Abook, use the MyISAM table format which uses the key_buffer_size option.

1. Open the my.cnf file in your editor
   

   /etc/my.cnf

2. In the above file, amend the following:
   

   key_buffer_size=256M

3. Save the changes and exit

We recommend 256MB for each of the above fields for every 2GB of RAM installed.