Performance considerations

Controller failures can affect performance.

The controller is designed to minimize performance impacts when running in a dual storage IOA configuration. When using RAID 5 and RAID 6, parity footprints are mirrored between the controller's nonvolatile memory, which causes only a slight impact to performance. For controllers with write cache, all cache data is mirrored between the controller's nonvolatile memories, which also causes only a slight impact to performance.

If one controller fails in a dual storage IOA configuration, the remaining controller disables write caching (if auxiliary cache is not also provided by the controllers) and begins to keep an additional copy of parity footprints on disk. This can significantly affect performance, particularly when using RAID 5 and RAID 6.