I have switch A and switch B and a server with 2Nic's, once connected to switch A and once connected to switch B. Is it possible to configure load balancing?If so, what will I have to configure?Is there a documentation about this?
load balancing between two NICs is possible, I am not sure what happens if you connect both to different switches. Check out this link from the Intel website that talks about the problem:
If you don't use Intel NICs, there is software from IP Metrics that allows you to load balance between NICs:
I know, that the server is able to load balance. I just want to know if it is still possible when the server is connected to 2 different switches.
How does the server implement loadbalancing?
If connected to a single switch, some NIC cards support bundling links into an Etherchannel, but afaik this is not possible connected to different switches.
Supposing you have a unique MAC per NIC, and a single IP address (that resolves to one of the MACs), then you will only loadbalance traffic from the host to the switch.
Traffic from switch to host will only go over the link that the IP addresses's MAC was learned on.
If you have a unique IP address per NIC, you can loadbalance bidirectionally but then you need some external mechanism (dns, loadbalancer) to distribute the load between the different IP addresses.