RAID Storage Space Reclamation for Heterogeneous Drives

The patent segments the storage array into two distinct groups: a performance group containing only high-performance drives, and a capacity group containing slower, higher-capacity drives. This segmentation allows each group to operate independently at its own optimal speed, eliminating the performance penalty of mixing heterogeneous drives in a single RAID array while still achieving the goal of using cheaper, higher-capacity drives for overall storage capacity.

The patent introduces a new dimension to storage array organization by creating separate RAID arrays for different drive types rather than mixing them in a single array. This dimensional separation allows the system to maintain homogeneous performance characteristics in the performance array while simultaneously utilizing the additional storage capacity of slower drives in a separate capacity array, thus achieving both goals without compromise.

The patent merges the capacity contributions from multiple slower drives into a dedicated capacity RAID array, where the total unused space from individual drives is consolidated into effective usable storage. By combining multiple drives of varying capacities in a capacity-optimized array configuration, the system eliminates the wasted space problem that occurs when mixing drives of different sizes in a performance-oriented array, achieving near-full utilization of all allocated storage space.