At http://trubix.blogspot.com I've written a blog on the importance of peripheral DBA skills. In the MySQL world, the following peripheral skills are very helpful for managing MySQL environments:
- LAMP skills - Linux, Apache, PHP/Perl/Python.
- Application Servers - knowledge of Apache, JBoss, LightHTTP, connection pooling, etc.
- Monitoring skills - Enterprise Monitor, Nagios, Cacti, etc.
- Ability to support developers - PHP, Java, .NET.
- Networking skills.