Data ONTAP classifies disks as one of four types for RAID: data, hot spare, parity or dparity. The RAID disk type is determined by how RAID is using a disk.
| RAID disk type | Description |
|---|---|
| Data disk | Holds data stored on behalf of clients within RAID groups (and any data generated about the state of the storage system as a result of a malfunction). |
| Hot spare disk | Does not hold usable data, but is available to be added to a RAID group in an aggregate. Any functioning disk that is not assigned to an aggregate but is assigned to a system functions as a hot spare disk. |
| Parity disk | Stores data reconstruction information within RAID groups. |
| dParity disk | Stores double-parity information within RAID groups, if RAID-DP is enabled. |