Which SyncMirror command mirrors an existing unmirrored aggregate where Data ONTAP selects the disk drive?

The command 'aggr mirror aggrY' without any disk-specification flags instructs Data ONTAP to mirror the named aggregate and internally select the appropriate drives for the mirror plex. No explicit disk arguments are provided, so the system applies its own selection logic based on available spare disks. This is the correct syntax when the administrator wants ONTAP to handle drive selection automatically.

The '-m' flag is not a recognized option in this context for triggering automatic disk selection during an aggregate mirror operation.

The '-d 12@144' argument explicitly designates which disks to use, meaning the administrator - not Data ONTAP - is performing the disk selection.

Combining an unrecognized '-m' flag with an explicit disk specification does not represent the syntax for letting ONTAP auto-select drives for mirroring.