Hi,
Assuming it is flexclone, the clone volume shares the parent volume blocks. If somebody wants to use the flexclone volume (QOS applied), the juntionpaths of both volumes are different. QOS is not really applied to physical data blocks hence It does not effect the source volume performance.
Hope this help.
Renifa.
If this post resolved your issue, help others by selecting ACCEPT AS SOLUTION or adding a KUDO.