Thanks to the good Support at DELL. The secret is you have to create a separate group on the switch for every esx-host. On the esx side you have the config with one lacp/lag group. But on the side of the switch you need 2 groups for two hosts. VMware should have made this more clear I think.
I would like to use the LACP/LAG feature in vSphere 5.5. So I created a new vDS and an LAG group. 2 NICs per host should be use for that. We use 2 hosts, so in total 4 ports are involved. Basicly you can view a scheme at vmwares KB article 2051826 ([URL] Problem is only 2 of the links in lacp group are active, while the other 2 are inactive. Active is only one of the esx hosts, it depends which ports are going to be active first. Any advice? Anyone have a config like that working? Best regards, Alex Relevant config for switch: !Current Configuration:!System Description "PowerConnect 6248P, 3.3.7.3, VxWorks 6.5"!System Software Version 3.3.7.3!Cut-through mode is configured as disabledstackmember 1 5member 2 5exitconfigure interface ethernet 1/g8channel-group 3 mode autodescription 'ESX2_vmnic5'spanning-tree disableswitchport mode generalswitchport general ingress-filtering disableswitchport general allowed vlan add 20 taggedexit   interface port-channel 3description 'ESX'hashing-mode 6spanning-tree disableswitchport mode generalswitchport general ingress-filtering disableswitchport general allowed vlan add 20 taggedexit  
LACP group doesn't work with 2 stacked DELL PC 6248 and 2 ESXi 5.5