Hi Ramesh3,
In a volume split operation, any space savings in the parent volume is un-deduplicated first then copied to the clone. This also applies to data that is also compressed. Both of these will consume aggregate free space. Once the split is complete, the data on the clone can then re-deduplicated and re-compressed.
More information can be obtained here, specifically at the top of page 69: NetApp Data Compression, Deduplication, and Data Compaction
Regards,
Team NetApp
Team NetApp