If you are like me looking at Microsoft documentation thinking you can just use BizTalk server to connect to a load balanced SAP via message server, you are wrong. It turns out even for this scenario (type B) BizTalk still needs a gateway service and a gateway host. Not a SAP guy at first place, but it seems to me you have to ‘cluster’ the gateway host as well to achieve HA.

So, you have to cluster both message server and gateway host for BizTalk to connect? Sad for SAP guys..