What is the advantage of persistent message delivery compared to

Question :What is the advantage of persistent message delivery compared to
nonpersistent delivery? (JMS)
Answer :If the JMS server experiences a failure, for example, a power outage, any
message that it is holding in primary storage potentially could be lost. With
persistent storage, the JMS server logs every message to secondary
storage. (The logging occurs on the front end, that is, as part of handling
the send operation from the message producing client.) The logged
message is removed from secondary storage only after it has been
successfully delivered to all consuming clients