If you are not planing to use Human Task / User Tasks in your processes you will be ok without the Human Task Server. Remember that you can also set up a local task service without any transport (Mina or HornetQ).
Thank you for your reply,
Actually, I am planning to use several human task/user tasks in my process. Does that mean I have to set up the task service?
What I don't understand is that in non-persistent environment, I do not have task service and the whole process works fine. But in persistence enviroment without a task service, when I try to complete a human task work item, nothing happened...that task never exits....Do I have to complete the task first and then complete the work item, to let the process comtinue?