A storage access system provides consistent memory access times for storage media with inconsistent access latency and reduces bottlenecks caused by the variable time delays during memory write operations. Data is written iteratively into multiple different media devices to prevent write operations from blocking all other memory access operations. The multiple copies of the same data then allow subsequent read operations to avoid the media devices currently servicing the write operations. Write operations can be aggregated together to improve the overall write performance to a storage media. A performance index determines how many media devices store the same data. The number of possible concurrent reads varies according to the number of media devices storing the data. Therefore, the performance index provides different selectable Quality of Service (QoS) for data in the storage media.