HP XP External Storage Software User Guide (T1706-96018, November 2011)

Figure 6 Alternate path mode is Single mode
• Alternate path mode is Single mode and at least one alternate path is in Standby status.
Figure 7 (page 24) shows an example of when the alternate path mode is Single mode and
there are alternate paths in Normal and Standby status. Figure 8 (page 24) shows another
example of when the alternate path mode is Single mode. In Figure 8 (page 24), there are
alternate paths in Standby status only.
When an error occurs in the path used for I/Os, the I/O execution path switches to the path
with the second highest priority in Normal status (Figure 7 (page 24)). If there is no path in
Normal status other than the path used for I/Os, the status of the path in Standby status
automatically changes to Normal and the I/O execution path switches to that path
(Figure 8 (page 24)).
NOTE: When the external array is an EVA 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.
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