HP StorageWorks XP Remote Web Console Software - Manual (Page 17)

External Storage XP user guide 17
NOTE: When the external disk array is an EVA disk array, as you restore the path with the highest
priority, the I/O execution path switches back to the restored highest priority path. In this case, the status of
the path for which the status changed to Normal when the error occurred changes back to Standby.
Figure 7 Alternate path mode is Single mode with alternate paths in Normal and Standby
NOTE: External disk arrays with Asymmetrical Active/Active (AAA) controllers, such as the Hitachi
Thunder, are an example of Figure 7 . A notable characteristic of using AAA controller disk arrays as
external storage is that paths to alternate ports on the owning controller for a given external LU are seen as
Normal status, but I/O load balancing does not occur (either across controllers or across ports to the
owning controllers). Paths to the non-owning external controller’s ports are shown as Standby status.