DIAGNOSTIC

A disk can change from an ONLINE state to a DIAGNOSTIC state if the application detects problems that are related to disk performance or significant number of I/O errors. It can also change into this state if it fails a SMART test or SMART attributes fall below threshold. The purpose of the DIAGNOSTIC state is to allow the operator to investigate whether the disk needs to be replaced or if it is healthy enough to resume operation within the system.

In a DIAGNOSTIC state, read and write operations to the disk are not supported. Existing slices on the disk are preserved indefinitely.

DIAGNOSTIC disks are considered "quarantined" and are occasionally referred to as so throughout the documentation.