Volume names must be unique for a storage system. When Data ONTAP detects a duplicate volume name, it renames one of the volumes, but the substitute names it uses can cause problems, so you need to take corrective action if that happens.
When Data ONTAP detects a potential duplicate volume name, it appends the string "(d)" to the end of the name of the new volume, where d is a digit that makes the name unique.
For example, if you have a volume named vol1 and you copy a volume named vol1 from another storage system, Data ONTAP renames the newly copied volume to vol1(1).
Renaming the volume prevents the name of the volume from changing unexpectedly later on.
Any volume whose name contains those characters cannot be exported to NFS clients.