Every Storage Virtual Machine (SVM) has a root volume that contains the paths where the data volumes are junctioned into the namespace. NAS clients' data access is dependent on the health of the root volume in the namespace and SAN clients' data access is independent of the root volume's health in the namespace.
The root volume serves as the entry point to the namespace provided by that SVM. The root volume of the SVM is a FlexVol volume that resides at the top level of the namespace hierarchy and contains the directories that are used as mount points, the paths where data volumes are junctioned into the namespace.
In the unlikely event that the root volume of an SVM namespace is unavailable, NAS clients cannot access the namespace hierarchy and therefore cannot access data in the namespace. For this reason, it is best to create a load-sharing mirror copy for the root volume on each node of the cluster so that the namespace directory information remains available in the event of a node outage or failover.
You should not store user data in the root volume of an SVM. The root volume of the SVM should be used for junction paths, and user data should be stored in non-root volumes of the SVM.