If the number of servers in a server pool falls below the value of the MIN_SIZE attribute for the server pool (such as when a server fails), based on values you set for the MIN_SIZE and IMPORTANCE attributes for all server pools, Oracle Clusterware can move servers from other server pools into the server pool whose number of servers has fallen below the value for MIN_SIZE. Oracle Clusterware selects servers from other server pools to move into the deficient server pool that meet the following criteria:
For server pools that have a lower IMPORTANCE value than the deficient server pool, Oracle Clusterware can take servers from those server pools even if it means that the number of servers falls below the value for the MIN_SIZE attribute.
For server pools with equal or greater IMPORTANCE, Oracle Clusterware only takes servers from those server pools if the number of servers in a server pool is greater than the value of its MIN_SIZE attribute.