Dynamic reallocation of physical storage

A data processing system, comprising:

• at least one processing system;
• and
• a storage system communicatively coupled to the processing system for transferring data in response to I/O requests from the processing system, the storage system including a plurality of disk units and a storage control system, the storage control system including a control unit and a memory having a computer program for causing the control unit to respond to I/O read requests from the processing system by
• establishing a logical volume management comprising a number of logical volumes, each of which stores the same data as the other logical volumes, each of which maps to a corresponding one or more of the plurality of disk units;
• selecting a one of the logical volumes in response to an I/O read request received from the processing system to read the data from a one of the plurality of disk units corresponding to the selected logical volume;
• maintaining values indicative of usage of the plurality of disk units;
• and
• periodically checking the values to change the number of logical volumes.

A multi-processor system comprising:

• a plurality of processor systems;
• and
• a storage system, including a plurality of disk units, communicatively coupled to the plurality of processor systems for storing data on or retrieving data from the plurality of disk units in response to I/O write or read requests, respectively, the storage system including a control unit and a memory coupled to the control unit, the memory storing a computer program for causing the storage system to distribute I/O read requests from the plurality of processor systems by
• establishing a logical volume management comprising a number of logical volumes, each of which stores the same data as the other logical volume, each of which maps to a corresponding one or more of the plurality of disk units;
• selecting a one of the logical volumes in response to a request to read data from the processing system to read the data from a one of the plurality of disk units corresponding to the selected logical volume;
• maintaining values indicative of usage of each of the plurality of disk units;
• and
• periodically checking the values to change the number of logical volumes.

In a data processing system including at least one data processor and a control unit coupled between the processor unit and multiple disk storage units for communicating articles of data therebetween in response to read and write requests received from the processor unit, the control unit operating to receive a write request to write multiple copies of the data to the multiple disk storage units, a method of dynamically distributing read requests that includes the steps of:

• receiving a read request to read data at the control unit;
• assigning the read request to a one of the disk storage units having a copy of the data to read the data therefrom;
• monitoring each read request assigned to each of the multiple disk storage units;
• and
• periodically increasing the number of the multiple disk storage units if the assigned read requests are greater that a predetermined first value.