This chapter discusses the cluster interconnect technologies that are supported under Cluster Service. Since Microsoft built its Cluster Service product to support industry standard hardware, what we discuss here applies equally well to clustering solutions from other vendors. We will take the time to go over some of the nuts and bolts of SCSI technology because contrary to what the marketers and press would like you to believe, SCSI is not going away any time soon. SCSI meets the needs of many of those installing clusters today and will continue to be a good fit for certain types of applications. It is certainly the technology of choice for cost-conscious customers looking to purchase smaller cluster configurations. By small, we mean cluster-in-a-box solutions configured with no more than two nodes. The cable length limitations associated with SCSI are not really a factor when everything is contained inside one enclosure. Further, the problems associated with the SCSI bus device priority order are not as much of an issue when the size of the cluster is limited to two nodes. On the other hand, customers who are looking to build very large cluster installations will probably look at SAN technology (e.g., Fibre Channel). SCSI has a long track record in the field, and, more important, it's a very cost-effective solution.