Storage system and load distribution method for storage system

A load distribution method for a storage system configured by including a plurality of computer systems coupled together via a network,

• wherein each of the computer systems includes an administrative server and a controller that controls execution of execution targets including at least either one of an application, a virtual machine, and a container, and collects an operation status of resources to be used to execute the execution targets;
• and
• wherein the administrative server judges whether the operation status exceeds a threshold value or not;
• and
• if the administrative server detects that the operation status exceeds the threshold value,
• the administrative server:
• calculates a first index for each of the execution targets on a basis of information about at least either one of cost, credibility, and performance when the execution target which operates in one of the computer systems is migrated to another one of the computer systems and is caused to operate in an other computer system, and indexing information which indicates laws or rules applied to the computer system by using indexes;
• acquires, from the other computer system, a second index which uses a dimensionless quantity to indicate a degree of selection of the other computer system as a migration destination of the execution target;
• and
• decides the computer system which is the migration destination of the execution target from among the plurality of computer systems other than the one computer system on the basis of either one or both of the first index and the second index.