High Capacity (HC) and Extended (XT) Oracle Exadata Storage Server models have a disk controller that contains a write-back cache, which is separate and distinct from the write-back flash cache.

A multiple-bit ECC error on the disk controller cache can crash the server, resulting in the loss of unflushed data in the disk controller cache and leaving stale data on the disks. If not handled carefully, such errors are severe and can result in data loss.

Oracle Exadata System Software release 21.2.0 supports automatic recovery following a disk controller cache failure. Where possible, this feature automatically detects the problem and copies data from other mirrors to recover all of the disks in the failed server.

Minimum requirements:

• Oracle Exadata System Software release 21.2.0