As expected (CI No 3,083), Digital Equipment Corp is to add support for up to eight nodes in TruCluster Production Server configurations of its AlphaServers Unix machines. Eight-node configurations are due this quarter, and the company is promising support for 16-node configurations within a year. The clusters will support shared tape subsystems and use a new version of Digital Unix, numbered 4.0C. New versions of the Memory Channel interconnect architecture, which tie the servers together, plus multiple active cluster interconnects, will provide the additional bandwidth to support more nodes than the four currently available in Production Server configurations. DEC says the new configurations will give it the opportunity to trounce its own 30,390 tpmC benchmark record. Current Production Server clusters support redundant Memory Channel boards for hot-standby operation, but they fire up only when a node fails. With the new release – multiple active interconnects – the second controller will be active and the system capable of performing some level of load-balancing. New Production Server configurations will also support AlphaServer 1000A systems, each with four processors. Memory Channel 1.5 is a performance enhancement to the existing 1.0 Memory Channel hardware, which shipped last December. A further revision, Memory Channel 2.0, will add a new crossbar hub, providing the higher overall cluster bandwidth needed to support the eight-node configurations. Over the next four quarters, DEC plans to increase the bandwidth of individual links by three times and hub bandwidth by a factor of eight, pushing the number of nodes supported up to 16 and increasing the maximum distance between nodes to 30 feet from 10 feet using copper cables, and to 100 yards using fiber. DEC says it will offer disaster tolerance around the first quarter of 1998 and a cluster file system in the second quarter. Production Server is DEC’s highest level of clustering technology, implementing the Encore Computer Corp-based Memory Channel interconnect and using Oracle Parallel Server or Informix XPS parallel databases. TruCluster Application Server implements the DECsafe SCSI-based fail-over software, while the basic TruClustering option offers logical storage management and a log-based file system.