6027-1807 [E] NSD nsdName is using Persistent Reserve,
this will require an NSD server on an osName node.
Explanation
A client tried to open a globally-attached NSD disk,
but the disk is using Persistent Reserve. An osName NSD
server is needed. GPFS only
supports Persistent Reserve on certain operating systems.
User response
Use the mmchnsd command
to add an osName NSD server for the NSD.