The accounts and domains settings are by default stored in the binary files in Merak\config folder, but you can configure Merak to store that in a database also. You can store also logs in a database, but it's not recommended.

You can find the groupware database connection settings in the Administration interface/Groupware/General/”DB Settings...” dialog, the anti-spam database connection settings can be found in the Anti-Spam/General/General/”DB Settings...” dialog and the account database settings can be set in the System/Storage/Accounts/”DB Settings...” dialog (after you enable database account storage).

Supported databases

The Merak 9 (Windows) installer lets you choose whether you plan to use Merak as small or large server - the basic installation for < 100 accounts and advanced installation for 100+ accounts. This question is asked because of database storage. There are basically 2 types of databases - file databases and database servers. The file databases are suitable only for smaller servers - they don't need any additional programs to be installed, but they don't handle big loads well. The database servers need to be installed and configured, however they are able to handle the more traffic. The account database storage is recommended for Merak with more than 500 accounts, the dedicated SQL server is recommended for Merak with more than few thousand accounts.

The default database for basic Windows Merak 9 installation is SQLite database, in versions prior to Merak 9 the default database was MS Access database. The MySQL database for versions 9.1 and older was needed for Linux Merak installation, in newer versions the default database will be also SQLite.

Generally Merak supports syntax of these database servers and database engines: MS SQL, MySQL, InterBase, Oracle and Firebird, MS Access and SQLite. The syntax is important because of difference between the string variable type of each SQL server. The "Default" syntax is universal syntax, but it doesn't use full potencial of the specific servers, so it's better to specify the correct server syntax.

Database server settings and connection settings

• ODBC (Open DataBase Connectivity) - the ODBC DSN (Database Source Name) is needed to connect to MS Access database, MS SQL, InterBase and Oracle servers. The MySQL and FireBird database can use either it's own drivers or ODBC.

  For more info please see these FAQs about ODBC:

  - How to set ODBC DSN for MS Access database

  - How to set Merak to use ODBC with MS SQL server

  - How to set Merak to use ODBC with MySQL

• SQLite - the SQLite database doesn't need the ODBC DSN or any additional driver installation. The database files are installed with Merak 9+ regardless the currently selected database settings (the along with SQLite driver).

  The groupware database is located in the Merak\calendar\groupware.db file. The Groupware/General/”DB Settings...” for this configuration are:

  

  The anti-spam database is located in the Merak\spam\antispam.db file. The Anti-Spam/General/General/”DB Settings...” for this configuration are:

  

• MySQL - you don't have to use ODBC to connect to MySQL server from Windows version of Merak, you can connect directly to the MySQL server using the driver from your version of MySQL server. You can find it in the MySQL server installation folder:
  MySQL server <version>\bin\libmysql.dll
  You should either add this path to Windows system path or copy this file to Windows\system32\ to be able to connect to MySQL server without ODBC.

  Note: The libmysql.dll library was part of the installation in versions prior to Icewarp server 9.1. It is strongly recommanded to delete Merak\libmysql.dll file and use the library of your current MySQL server instead.

  MySQL database is needed for Linux installation of Merak 9.1 or older (in case you want to use Groupware and Anti-Spam features mentioned above). Required libraries are in most cases installed along with Linux.

  Here is the example how you can create database for Merak:

  

  The ”DB Settings...” on Windows for both groupware and anti-spam are for the local server with example database from above:

  

  The typical “DB Setting...” for the same database on Linux:

  
  
  

Database Migration

Merak contains integrated database migration tool. You can use it to migrate from one type of database to another (to the same type too, of course), as well as to backup your database. The database migration is located in the Administration interface System/Tools/Database Migration section.

You should select the database type (whether you migrate account, groupware or anti-spam database) and fill the DB connection settings according to instructions in previous chapter.

Database migration process drops destination database tables (not all, only those, which belong to selected database type, and only if the tables exist, naturally), and creates new tables with the same data as in the source database.

Troubleshooting

All database errors are recorded into Merak error log (you can find it in the Administration interface Status/Log/Error log). So if you experience any problems with the database check the log first.

As mentioned above, the file based databases are not suitable for larger servers (100+ accounts), so these servers should migrate database the some SQL server – this may resolve many problems.

Jan Ramba, jan (at) icewarp (dot) com