Hello Paul,
- No data means, it will only check the file modify time, attributes and wont check the actual data.
- You can use sync instead of isync because it will create index and compare data next time you resume sync.
- Since the xcp sync does not scan the actual data ever and instead it looks into the database (index) that XCP maintains, we dont have a -nodata option with XCP sync.
- It compares the SRC and DST via the database (index) that it maintains.
- Matching KB: https://kb.netapp.com/on-prem/ontap/da/XCP/XCP-KBs/What_is_xcp_isync
Hope my answers help.