Underperforming disks affect the performance of all disks because work is distributed equally to all disks. For example, if a disk is performing 30% slower than other disks, then the entire system's I/O capacity will be 30% lower.

When an underperforming disk is detected, it is removed from the active configuration. Oracle Exadata Database Machine then performs a set of performance tests. If the problem with the disk is temporary and it passes the tests, then it is brought back into the configuration. If the disk does not pass the tests, then it is marked as poor performance, and an Auto Service Request (ASR) service request is opened to replace the disk. This feature applies to both hard disks and flash disks.