HP StorageWorks 4000/6000/8000 .HP StorageWorks SAN Design Reference Guide, Pa - Page 425

When adding new switches, avoid fabric segmentation. For more information, see "Fabric segmentation errors" on page 426. Cascaded fabric expansion Expand a cascaded fabric by connecting a new switch to an available port on an existing switch. If no ports are available, remove devices from an existing switch, connect the new switch to those ports, and then reconnect the devices to the new switch. Meshed fabric expansion Expand a meshed fabric by connecting a new switch to available ports on an existing switch. If no ports are available, remove devices from an existing switch, connect the new switch to those ports, and then reconnect the devices to the new switch. Ensure that multiple paths (ISLs) connect the new switch to the meshed fabric. Ring fabric expansion Expand a ring fabric by adding a switch to the ring. Add new switches cascaded off the ring, up to the maximum number of switches supported in a single fabric. When expanding outside the ring, ensure that communicating devices are connected by no more than seven hops. Core-edge fabric expansion Expand a core-edge SAN fabric by adding edge switches. Connect edge switches to available ports on the backbone switches. If the current SAN contains only one core switch, add another. Connect edge switches to ports on the new core switch. SAN fabric merging You can merge independent fabrics into a single, larger fabric. Merging enables you to: • Provide more resources to independent SAN fabrics. • Share the resources in two or more fabrics. • Make information in one SAN available to servers in another SAN. • Connect geographically dispersed fabrics into a single SAN. During initial login, the discovery process determines whether the fabrics are compatible. If not, segmentation occurs and they continue to operate as separate fabrics (see "Fabric segmentation errors" on page 426). When fabrics merge, the zone configuration databases are updated to include the zone configurations of each fabric. If a nonzoned fabric merges with a zoned fabric, all zoning information is proliferated to the nonzoned fabric switches. A zone configuration that is enabled at the time of the merge is also enabled on the nonzoned fabric switches. Devices in the nonzoned fabric are not accessible until you add them to the current configuration. SAN Design Reference Guide 425