That IO module (303-081-105B) is the dual-port, 10Gb Optical Interface card. It only operates at 10Gb.  You can use either the optical SFP (using optical cable OM3) or the Twinax cable. The Twinaxx cable included the SFP as part of the cable, the cable is copper. Both operate at 10Gb. You could just remove the optical SFP and insert the Twinax cable to have two ports using the copper cable.  EMC does not support Passive Twinaxial cables in an iSCSI or FCOE environment.EMC only supports Active Twinaxial cables in an iSCSI or FCOE environment.We currently support EMC, Brocade and Cisco cables.  The SFP-H10GB-CU7M appears to be a Cisco passive cable - you should check with Cisco to see if this cable is Active or Passive.  glen
vnx 5300 unified came with one IO module per SP (303-081-105B Rev: B07). Each module has two ports, one a 10GB copper iSCSI (SFP-H10GB-CU7M), and the other a 10GB Optical port (FTLX8571D3BNL-E5). Can I simply swap out the Optical connector for another copper one?  Also, what is the limit for 10Gb copper. Can I install another I/O module with dual copper?
replace 10G optical port with 10G copper?