Strategies for Data Protection - Brocade

Storage-Centric vs. Network-Centric SAN ArchitecturesVirtual FabricsIt is also possible to segregate departmental or business unit applicationson a shared SAN infrastructure by dividing the physical fabric intomultiple logical fabrics. Each virtual fabric (VF) behaves as a separateautonomous fabric with its own SNS and RSCN broadcast domain,even if the virtual fabric spans multiple fabric switches, as shown inFigure 7. To isolate frame routing between the virtual fabrics on thesame physical ISL, VF tagging headers are applied to the appropriateframes as they are issued, and the headers are removed by the switchbefore they are sent on to the designated initiator or target. Theoretically,the VF tagging header would allow for 4,096 virtual fabrics in asingle physical fabric configuration, although in practice only a few aretypically used.Virtual fabrics are a means to consolidate SAN assets, while reducingmanagement complexity to enforce manageable SAN units. In theexample shown in Figure 7, each of the three virtual fabrics could beadministered by a separate department with different storage, security,and bill-back policies. Although the total SAN configuration can bequite large, the division into separately-managed Virtual Fabrics simplifiesadministration, while leveraging the data center investment in SANtechnology.Strategies for Data Protection 13