For flyway (http://code.google.com/p/flyway) CI integration tests on Jenkins (Ubuntu) we use a Windows XP image on VirtualBox 4.1 on which the the supported DBs (DB2, MySQL, PostgreSQL, Oracle, SQLServer) are installed. Everything works fine and we connect via virtualbox port forwarding feature to the DBs on the virtual machine.
But only for MySQL the simple test's run extremely slow (minutes instead of several seconds) and we had to raise the timeout to get them green.
The tests are running fast if a local MySQL instance is used.
Does anybody have an idea what may be the reason for this, or how we can track/analyze the problem?