HP Surestore 64 Planning Guide - Page 121

Configuration Planning Tasks Task 15: Plan a Multiswitch Fabric (Optional) If a multiswitch fabric topology is to be implemented, carefully plan the physical characteristics and performance objectives of the topology, including the proposed number of directors (or other elements) in the fabric, characteristics of attached devices, cost, nondisruptive growth requirements, and service requirements. When two or more directors are connected through ISLs to form a fabric, the directors must have compatible operating parameters, compatible name server zoning configurations, and unique domain identifications (IDs). Planning for a fabric must be carefully coordinated with planning for zoned configurations. The following factors should be considered when planning for a multiswitch fabric: • Fabric topology limits Consider the practical number of director fabric elements (maximum of 31), number of ISLs per element (maximum of 32), hop count (two), and distance limitations (limited by port type and cable availability). • Bandwidth Consider using multiple ISLs to increase the total bandwidth available between two directors. • Load balancing If heavy traffic between devices is expected, consider installing multiple ISLs to create multiple minimum-hop paths for load balancing • Principal switch selection If required, plan which director is to be assigned principal switch duties for the fabric. • Critical operations Consider routing paths that transfer data for critical operations directly through one director and not a fabric. Planning and implementing a multiswitch fabric is a complex and difficult task. Consult your local HP sales office for the latest configuration information. Task 15: Plan a Multiswitch Fabric (Optional) 107