If I want to use MTS I need to set MTS_SERVERS =>1.
OK this sounds logical but if I set MTS_SERVERS=5 and if there is no need for so many shared servers they stay idle, and if there are many users, Oracle server will dinamically create as much shared servers as he needs (and when busy time is gone we will have again 5 shared servers.)
I think it is better if this parameter is TRUE/FALSE and not numerical value.
You can use MTS_SERVERS=1 and MTS_MAX_SERVERS=<what_ever_you_want> to specify maximum number of MTS servers. If Oracle does not need such amount of servers so far it removes idle processes from memory.