112 External Storage XP for the XP12000/XP10000
Name found on the EVA disk array. You can identify the EVA disk array’s logical volume by this World
Wide LUN Name.
Figure 49 Configuration example for which logical volumes can only be identified by characteristic
Alternate path’s behavior when an EVA disk array is connected
When an EVA disk array is connected, the alternate path’s behavior differs depending on the EVA disk
array’s microprogram version.
The alternate path’s behavior differs between EVA disk arrays of the microprogram version shown below
and EVA disk arrays of earlier microprogram versions:
• Disk array type: EVA3000/5000
microprogram version 4.000 or later
• Disk array type: EVA4000/6000/8000
microprogram version 5.031 or later
To replace the EVA disk array’s microprogram, check whether the alternate path’s behavior changes as a
result of changing the microprogram version. If the alternate path’s behavior changes, perform External
Storage XP’s Delete LU operation to release the setting for the EVA disk array volume’s mapping before you
actually replace the microprogram.
See the EVA disk array manuals for more information how the alternate path’s behavior changes.
Required volume capacity for emulation types
When you map an external LU as a local disk array internal XP LDEV, you must specify the
XP12000/XP10000 emulation type for the mapped LU.
The capacity required for the LDEV to be mapped is the total capacity of the data area for storing actual
user data and the control information area for storing control information. The capacity of the data area
(called base data area capacity) and the capacity of the control information area (called control
information area capacity) depend on the emulation type. The minimum capacity of the data area for
Customized Volume (CV) (called minimum data area capacity) also depends on the emulation type.
Use the following equation to calculate the minimum capacity required for an LDEV (minimum LDEV
capacity) for each emulation type:
Minimum LDEV capacity = Minimum data area capacity + control information area capacity
If the external LU’s capacity is less than this minimum LDEV capacity, the emulation type cannot be
specified.
Use the following equation to calculate the base LDEV capacity for each emulation type:
Base LDEV capacity = Base data area capacity + Control information area capacity
When the external LU’s capacity is less than the emulation type’s base LDEV capacity, one CV is created in
the external LU as you map the volume. When the external LU’s capacity is more than the emulation type’s
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