I am planning to buy a network card for a new academic research server, which will be used in a SFP+ environment. I would like to evaluate the X520-DA2 (SFP+) and the X520-QDA1 (QSFP+).
I wonder if a X520-QDA1 card can be directly linked with two different SFP+ devices simultaneously, using a Direct Attach cable, such as the X4DACBL3, that provides 4x10 GbE connections.
If that is correct, how many network devices/interfaces will be available at OS level.
From the ixgbe driver's README:
"- 82599-based QSFP+ adapters only support 4x10 Gbps connections.
1x40 Gbps connections are not supported. QSFP+ link partners must be
configured for 4x10 Gbps."
Does it mean that the card provides four interfaces (i.e, eth0, ... eth3)?
Each port of multi-port network adapters usually advertised to OS level as separate Ethernet device, so yes, you will have eth0, ... eth3). There is a teaming function of Intel driver to combine ports and/or adapters into single link, but technically this will create new virtual ethernet port and real ports will drop configuration and goes into unmanageable state.