Patent ID: 6880058

Claim:
A computer system with a storage system having reconfigurable logical volumes comprising: a plurality of computers; a storage system operatively coupled to said computers and comprising a plurality of inner logical volumes and an LU controller said inner logical volumes; and a management console to communicate instructions to change a logical volume configuration of said logical volumes, said LU controller comprising an LUN map designating an association among an outer LUN, one or more inner LUNs, and a computer ID, said outer LUN designating an outer logical volume that can be accessed by one of said computers, each of said inner LUNs designating one of said inner logical volumes whereby said outer logical volume can be associated with one or more of said inner logical volumes, said computer ID designating one of said computers, said LU controller responsive to an instruction to change said logical volume configuration by modifying said LUN map according to said instruction, wherein prior to said LUN map being modified, a first outer LUN and a first computer ID are associated with a first inner LUN, wherein subsequent to said LUN map being modified, said first outer LUN and first computer ID are associated with a second inner LUN different from said first inner LUN, wherein said instruction to change a logical volume configuration includes said first inner LUN and a requested size, wherein said LU controller is configured such that if a free storage area exists which has a size that is larger than said requested size plus the size of said inner logical volume designated by said first inner LUN, then said LU controller copies data stored in said inner logical volume designated by said first inner LUN to said free storage area, and rewrites said LUN map to correlate said free storage area with said first outer LUN, with said first computer ID, and with said second inner LUN, said second inner LUN being associated with said free storage area, wherein said LU controller is further configured such that if said free storage area does not exist in said storage system, then said LU controller rewrites said LUN map to correlate said first outer LUN with said logical volume designated by said first inner LUN and with any free storage area in said storage system.