Bring LUNs online with System Manager - ONTAP 9.7 and earlier
You can use the LUN Management tab in ONTAP System Manager classic (available in ONTAP 9.7 and earlier) to bring selected LUNs online and make them available to the host.
Any host application accessing the LUN must be quiesced or synchronized.
Click Storage > LUNs.
In the LUN Management tab, select one or more LUNs that you want to bring online.
Click Status > Online.