Storage controller and a method for recording diagnostic information

A storage controller for recording diagnostic information in a storage system having multiple storage devices, the storage controller comprising:

• a storage device manager for allocating a storage device in the storage system as an allocated storage device for storing diagnostic data, wherein the diagnostic data is stored in an area of the allocated storage device that is normally allocated for customer data, wherein the allocated storage device is a reserve storage device that is normally reserved for disaster recovery;
• a diagnostic logic for generating diagnostic data regarding operation of a storage controller of the storage system;
• and
• a buffer used to record and write batches of diagnostic data to the allocated storage device, wherein the storage controller uses a buffering technique to record and write the batches of diagnostic data to the area of the allocated storage device.