Multiple iSCSI Connections to SAN Controller

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My SAN has 8 available Ethernet ports - 4 per controller.

My 3 Hyper-V hosts will access the SAN via a switch.

1. Should I utilise all 8 available Ethernet ports on the SAN?
2. Using all 8 available  Ethernet ports on the SAN - will it increase performance or only increase redundancy?
3. Is there a rule of thumb e.g. 3 Hyper-V hosts so use 6 SAN Ethernet connections (3 per controller)