Patent ID: 8838889

Claim:
For use with a storage system comprising a plurality of physical disks constituting a physical storage space, and a plurality of disk units, each comprising several of the plurality of physical disks, said physical storage space is configured as a concatenation of a plurality of RAID (Redundant Array of Independent Disks) groups, each RAID group comprising N+2 members; wherein the RAID groups are configured as RAID 6 groups and the number of members of a RAID group equals twice the number of disk units; a method of allocating a physical disk to a group member of a given RAID group, the method comprising: characterizing each pair of physical disks of the plurality of physical disks by a contention value being a number of RAID groups with members allocated to both physical disks in the pair; identifying among multiple pairs of physical disks one or more pairs having a minimal contention value, the minimal contention value being a contention value that is a minimum of contention values of all pairs; allocating said group member to a certain physical disk selected from physical disks comprised in said one or more pairs; wherein the allocating is performed such that every disk unit comprises no more than two allocated group members of said given RAID group.