Larger capacity data storage systems include many individual storage units, e.g., as seen in FIG. 3 above. The individual storage units may include HDDs, optical disks, SSDs (e.g., such as SSDs having non-volatile random access memory (NVRAM) technologies such as NAND Flash memory, NOR Flash memory, phase-change memory (PCM), magnetoresistive RAM (MRAM) and resistive RAM (RRAM)), etc. As noted above, data can be stored redundantly across these storage units using a mathematical erasure code so that data can be recovered without loss when one or more individual storage units fail. Moreover, an erasure code group represents the set of storage units in a storage system which together participate in an erasure code, independent of other storage units in the same storage system. Thus, an erasure code protected storage system includes at least one, and possibly many erasure code groups.

An erasure code is also typically implemented independently across a subset of the storage capacity of each storage unit, also referred to as a “strip” herein. Each of many strips in a storage unit may be protected by an erasure code applied against corresponding strips on the other storage units in the erasure code group. Moreover, a “stripe” includes one strip from each storage unit in an erasure code group, on which the erasure code is applied independently from other stripes on the same storage units.