Hadoop and MySQL Integration
Sqoop is a tool designed to import data from relational databases into Hadoop
https://github.com/cloudera/sqoop/wiki/
and a video about it http://www.cloudera.com/blog/2009/12/hadoop-world-sqoop-database-import-for-hadoop/
Hadoop is used for batch based jobs mostly on large sized semi structured data.. Batch in the sense even the shortest jobs is in the order of magnitudes of minutes. What kind of performance problem you are facing? Is it based on data transformations or reporting. Depending on that this architecture may help or make things worse.
As mentioned by Joe, Sqoop is a great tool of the Hadoop ecosystem to import and export data from and to SQL databases such as MySQl.
If you need more complex integration of MySQL including e.g. filtering or tranformation, then you should use an integration framework or integration suite for this problem. Take a look at my presentation "Big Data beyond Hadoop - How to integrate ALL your data" for more information about how to use open source integration frameworks and integration suites with Hadoop.