About Universal Volume Manager Operations 2-15
Hitachi Universal Storage Platform V/VM Universal Volume Manager User’s Guide
External
Port B
Port
WWN B
Internal
Volum e
External
Port A
Port
WWN A
External
Volume
External
Port C
Port
WWN C
Path
Priority 1
Path
Priority 2
Path
Priority 3
External
Port B
Port
WWN B
Internal
Volum e
External
Port A
Port
WWN A
External
Volume
External
Port C
Port
WWN C
Path
Priority 1
Path
Priority 2
Path
Priority 3
Error
: I/O
External Storage System
Legend
: Internal volume where the external volume is mapped
Local Storage System
External Storage System Local Storage System

Figure 2-6 When the Path Mode is Multi Mode

• When the path mode is Single mode

Figure 2-7 shows an example of the case when the path mode is Single

mode. 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.

Note: As you restore the path with the priority higher than the currently

used path, the I/O execution path is automatically switched to the restored

path that has the highest priority.