Traffic was not load balanced between the 2 gigabitethernet links, instead there was traffic on only one of them.
No relevant alarm. Only relevant system information is the output of display interfaces brief.
From this output we could see traffic above 1% on only one link. In traffic on that link was at 34%.
The resolve this issue the first option was to change the way packets are load-balanced on the S5700. On S5700 there is a per-flow load-balancing. That means that diffrent flows are load-balanced, a flow being identified by src/dst ip address and mac address. The solution was to change this behaviour to the default behaviour of the cisco device where packets are load-balanced only by src/sdt ip address.
The root cause of this issue is the way packets are load-balanced on Huawei eth-trunk as opposed to Cisco port-channel.
When ever using a eth-trunk with a cisco port-channel it is recommanded to use the same load-balancing scheme in order to avoid errors (good choice is load-balancing by source & destination ip address).