24 External Storage XP for the XP12000/XP10000
NOTE: As you restore the error path, use of the restored path automatically resumes.
Figure 5 Alternate path mode is Multi mode
NOTE: In Multi mode, active I/O load balancing occurs across external disk array ports and
controllers. The XP and EMC DMX are examples of external disk arrays that use Multi mode.
• Alternate path mode is Single mode
Figure 6 shows an example of when the alternate path mode is Single mode. 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.