TWINS SERVER proposes single, normal sized server (even rack-mountable), with all benefits deriving from hardware clustering. From architectural point of view, external structure is a pedestal case form factor 4U (4HE), where all internal electronic resources are redundant, placed inside two single modules: in both ones there are all single server typical components: motherboard, single processor, RAM, all optional added cards, etc., (all powered from a Power Unit Supply), and one hard-disk (powered from another, single dedicated PSU). Both single module servers are identical (optionally added PCI cards too), with an “Active-Passive” system. The hard disk drives are configured in RAID 1-MIRROR level .