The output of the FPolicy command run at the storage system contains a counter for the total number of request screened by that particular file policy. However, currently there is no way to understand the division between CIFS and NFS traffic.
Every client request that goes through FPolicy screening generates some extra CIFS requests for internal FPolicy communication. This is true for both CIFS and NFS clients requests. Currently there is no way to measure this extra traffic.
Yes, switching on FPolicy before doing any recalls has an impact on the performance. The impact of the performance depends primarily on how FPolicy is configured. It is therefore recommended that you do not turn on FPolicy before doing any recalls.
Yes, the performance of the slower server does affect the performance of the faster server. It is therefore recommended that servers with same capabilities are used while connecting to a storage system.
No, such data is not currently available for FPolicy.