In the VMware ESXi 4.x compatibility list, or Promise VessRAID iSCSI SAN has a footnote: "SP failover is not supported. Only SP port failover is supported" SP obviously means Storage Path", however I am unsure what is meant by this footnote, since all I can find when searching VMware documents for "port failover" is a reference to HBAs that hide the failover from the VMware kernel, which doesn't sound like a property of the iSCSI SAN target or its VMware initiator side settings.
So what does this footnote mean, which VMware settings cannot be used and which ones can. Promise support is mostly unhelpful, so asking them is unlikely to get a straight answer.