Citrix XENserver (at least up to Vers. 5.5) will not be able to reconnect correctly to a SCST driven iSCSI device. We experienced this Problem while rebuilding a lost primary OpenE Server. The XenServer will after all not be able to start the VMs and you have to remove the iSCSI Target from XENserver. For us it seems best practice is to build XENserver storage on top of IET and leave it that way. Maybe this is a lag of compatibility caused by the stoneage Kernel and necesssary backporting used or needed by XEN/XENserver.