HP StorageWorks XP24000 User Manual page 22

Figure 9 When the Path Mode is Single Mode
When the path mode is Single mode and there is at least one alternate path in the Standby
status
Figure 10 (page 23) shows an example of when the path mode is Single mode, and there
are alternate paths in Normal status and Standby status. Figure 1 1 (page 24) shows another
example of when the path mode is Single mode. For Figure 1 1 (page 24), there are alternate
paths in Standby status only.
When an error occurs in the path that is being used for I/Os, the I/O execution path is
switched to the path with the second highest priority in Normal status (see Figure 10 (page
23)). If there is no path in Normal status other than the path that is being used for I/Os, the
status of the path in Standby status is automatically changed to Normal, and the I/O execution
path is switched to that path (see Figure 1 1 (page 24)).
As you restore the path with the highest priority, note that only when the external storage
system is an EVA storage system, the I/O execution path is switched back to the restored
highest priority path. In this case, the status of the path for which the status was changed to
Normal when the error occurred changes back to Standby.
22 About XP External Storage Operations HP Confidential