I succesfully install multiple instances on the same host since many years (good old 3.23), my rule of the game is: different os user, different os user homedir, different my.cnf (with different port/socket) and start the server ecluding the possibility to read other than its own my.cnf with --defaults-file=/home/mysql-instance-x/my.cnf It works greatly and never had one problem (as long as you also start mysql client with --defaults-file=/correct/my.cnf)
Question: Why on Certification Study Guide, Chapter 42, Page 576, First Bullet it states: "Each server must have its own network interface(......) it will not even start properly if it discovers that its network interfaces are already in use(...)" Even if at the end it changes the version a little bit stating: ".....can share the same hostname. They can also share the same IP address as long as they listen on different TCP/IP port numbers." I find at least confusing,and I think that should be corrected, am I wrong? What do the masters think? Claudio