Your customer mentions that they have accidentally destroyed both root aggregates in their two-node cluster.

 If both root aggregates are destroyed in a two-node cluster, the cluster will be inoperable and the data will be inaccessible. To recover from this situation, you need to perform the following actions:

Install ONTAP from a USB device on one of the nodes. This will create a new root aggregate and a new cluster on that node.

Rejoin the second node to the re-created cluster. This will also create a new root aggregate on the second node and synchronize it with the first node.

Restore the cluster configuration and data from a backup, if available. References =

ONTAP 9 Documentation Center

Storage System Recovery Troubleshooting

Recovering from a root aggregate failure