Recording medium having load balancing program recorded thereon, load balancing apparatus and method thereof

A load balancing apparatus, comprising:

• a load monitoring unit configured to monitor load statuses of a plurality of servers, which are connected with a network, at predetermined time intervals;
• an initial distribution unit configured to distribute, upon receipt of an execution request of jobs of a batch process, jobs associated with the execution request only to one or more of the plurality of servers having a load lower than an initial distribution reference value, which indicates a level of load for which distribution of a job is allowed, based on the load statuses of the plurality of servers monitored;
• an adjustment unit configured to specify, in a case where a load of any one of the plurality of servers is higher than at least the initial distribution reference value and is lower than a redistribution reference value, which indicates a level of load for which a job being executed in a server is necessary to be redistributed to another server, when the load statuses are monitored, a server having a lowest load among the plurality of servers except the one of the plurality of servers, the specified server serving as a redistribution target of a job, thereby adjusting distribution of the jobs so that the load of the server serving as the redistribution target decreases to lower than a current load;
• and
• a redistribution unit configured to redistribute, in a case where a load of any one of the plurality of servers is higher than the redistribution reference value when the load statuses are monitored, a job being executed in the one of the plurality of servers to another server.

A load balancing method for servers, said load balancing method comprising:

• allocating a job to one or more servers having a load lower than a first reference value, respectively;
• reducing a load of a second server having a lowest load among said servers by a load balancing upon detection of a first server having a load that is higher than said first reference value and is lower than a second reference value;
• and
• reallocating a job of said any server to another server having the lowest load among said servers upon detection of any server having a load that is higher than said second reference value.