- Increase raid456 stripe cache size if needed to --grow the array.
The setting used unfortunately requires intimate knowledge of the
kernel, and it not reset when the reshape finishes.
+ - Change 'Device Size' to 'Used Dev Size' because it only shows how
+ much of each device is actually used, not how big they are.
Changes Prior to 2.5.6 release
- Fix bug which meant "bitmap=xxx" in mdadm.conf was not handled