HP Cisco MDS 9120 Cisco MDS 9000 Family Fabric Manager Configuration Guide - R - Page 597

Chapter 27 SAN Device Virtualization About SDV Send documentation comments to [email protected] • Clustering (multiple initiators) compounds the problem, and the failover procedure must be repeated for each server of the cluster. Think of a server cluster as a set of HBAs-any storage array FC ID changes must be performed for each HBA. SDV enables you to achieve the following performance targets: • Reduce the amount of time it takes for data migration, and ultimately the overall amount of downtime. • Easily scale to larger numbers of devices. Figure 27-4 illustrates the benefits of SDV. In this configuration, disk array Y replaces disk array X. When disk array X was deployed, the user created virtual devices for all the Fibre Channel interfaces using SDV. After data replication from disk array X was completed, the user briefly pauses activity on the application server and relinked disk array Y to the virtual devices used by the server, completing the swapout of disk array X. No zoning changes or host operating system configuration changes were required during the time-critical period when the swap was performed; this significantly minimized application downtime. Note The array administrator will likely have to perform actions on array Y for it to become a primary device and accept server logins before linking the virtual device to the array Y pWWN. Figure 27-4 Server SDV Example Storage Arrays X Y Physical to Virtual Mapping Virtual Device 159897 Key Concepts The following terms are used throughout this chapter: • Virtual device-The virtualized or proxy representation of the real device, which is registered with the name server and has a pWWN and FC ID. A virtual device exists as long as its real (physical) counterpart is online. The virtual device pWWN and FC ID must be unique and cannot clash with any real device pWWNs and FC IDs. • Virtual domain-Reserved by SDV to assign FC IDs to virtual devices. If the switch that reserved the domain goes down, another switch takes over its role using the same domain. • Primary device-The device that is configured as primary. By default, the primary device becomes the active device if it is online. OL-17256-03, Cisco MDS NX-OS Release 4.x Cisco MDS 9000 Family Fabric Manager Configuration Guide 27-3