1. A system comprising: a high speed private local area network (LAN); and a logical cluster of appliances comprising a plurality of physical sub-clusters of appliance nodes, wherein each node of said appliance nodes comprises a different generation node, wherein said plurality of sub-clusters are interconnected via said high speed private LAN, wherein a sub-cluster (N) of said plurality of physical sub-clusters comprises a first plurality of nodes of said appliance nodes, wherein said first plurality of nodes comprises an appliance node, wherein said appliance node comprises a virtualization node, a tape volume cache (TVC), a hierarchal storage node, and a library manager, wherein said virtualization node comprises a watchdog timer enabling said virtualization node to be restarted during a malfunction, wherein said TVC caches data read from an associated logical volume, wherein said hierarchal storage node uses tokens to determine which of said first plurality of nodes comprises a current data copy, wherein said library manager comprises a plurality of physical tape drives and a robotic accessor for transferring magnetic tape to said plurality of physical tape drives, wherein said sub-cluster (N) is associated with a plurality of (M) generation appliances of said logical cluster of appliances, wherein each appliance of said plurality of (M) generation appliances comprises a same type, category, and family of appliance, wherein (N) comprises a first cluster number, wherein (M) comprises a first generation number of a first generation comprising a first development configuration of appliances, wherein said plurality of sub-clusters, in combination, form a single logical cluster, wherein said sub-cluster (N) is connected to a sub-cluster (P) of said plurality of physical sub-clusters, wherein said sub-cluster (P) is associated with a plurality of (Q) generation appliances of said logical cluster of appliances, wherein each appliance of said plurality of (Q) generation appliances comprises a same type, category, and family of appliance, wherein (P) comprises a second cluster number, wherein (Q) comprises a second generation number of a second generation comprising a new development configuration of appliances with respect to said first generation, and wherein said first generation differs from said second generation.