Should master and slave have same mysql version?
Your replication configuration 5.5.11 -&gt; 5.5.30 is a supported configuration and there is no real justification for deploying a new slave using old software.

In fact, MySQL replication is supported across major releases as long as the two releases are consecutive, so 5.1.x -&gt; 5.5.x is supported and 5.5.x -&gt; 5.6.x is supported.

The only caveats are that the slave should be the same version as -- or newer than -- the master, and if you're doing circular replication, you should not have more than two versions of MySQL in the chain (and best practice suggests that they be identical in this case).

http://dev.mysql.com/doc/refman/5.5/en/replication-compatibility.html

If you are copying the files from another machine of a different version, don't forget to run mysql_upgrade on the new slave.