you can use the set command to specified how the size is displayed.
set -units GB
set -units MB
[-units {auto|raw|B|KB|MB|GB|TB|PB}] - Data Units
Use this parameter to specify the default units used when reporting data sizes.
Possible values are:
- auto - Auto-scale data size for human-readable output
- raw - Bytes without unit designation
- B - Bytes
- KB - Kilobytes
- MB - Megabytes
- GB - Gigabytes
- TB - Terabytes
- PB - Petabytes
The default setting is auto.
https://docs.netapp.com/ontap-9/topic/com.netapp.doc.dot-cm-cmpr-930/set.html
Hope this help.
PD: For your specific problem try to check the lun size and lun & igroup ostype