It is possible for you to resize and create a new LUN if “thin provisioning” function was applied (dynamic) to the existing LUN.
To check the previous settings:
Go Storage Manager -> iSCSI tab -> Click the target you wish to check -> Click LUN Poor -> Click the LUN that you wish you check in Mapped LUN (s) folder -> Click Unmap -> Click the LUN that you wish you check in Unmapped LUN(s) folder -> Click Edit -> If yes is selected under “Thin provisioning,” you can just slide the bar under to adjust the LUN size.
After the actions above, please don’t forget to map the LUN back to the target if needed.
Unfortunately, if thin provisioning function wasn’t applied (static), you need to break the LUN and then reassign your space. All the date will be destroyed afterwards, so make sure you back up all the data needed before actions. Also, please note that if the existing volume is full, it will not have enough space for thin provisioning to work. In that case, please add more space into the volume first.