Got a problem with NIC failover with iSCSI.
Setup: A server with 3 NICs. One NIC is local network, other 2 are SAN. Using Microsoft iSCSI Initiator. A managed network switch. A QNAP SAN, connected via iSCSI to server. Dual NIC, failover mode.
All works fine until (for testing purposes) you disconnect one of the server's SAN NIC's cables (well, actually just disable port on a switch). Then everything breaks, copying files stops, server most of the time loses all iSCSI mapped disks, etc. If disconnecting one of the cables on QNAP, all works just fine, without any noticeable delays.
So far, I've tried multiple Multipath Session / MCS connection configurations: Single session, multiple MCS (one connection, two connections, round-robin or failover for two connections) Two sessions, multiple MCS (one connection, two connections, round-robin or failover for two connections).
Doesn't matter which NIC is active, as soon as you try to do the failover it dies completely.
As much as I researched online everything shows that the failover should work that way, but it doesn't.
Any ideas? What am I doing wrong?