Software User Manual

External Storage XP user guide 33
LU’s capacity and each emulation type’s normal size. When mapping an external LU using emulation
types other than OPEN-V, an XP array management information area is required in the mapped LU.
This means that the capacity available after mapping is slightly smaller than the actual external LU
capacity. Available capacity decreases by the size of the XP array management information area,
and all prior data must be considered lost. For more information, see the HP StorageWorks Flex Copy
XP user guide.
Figure 12 shows an example where the external LU’s original capacity is larger than (or a multiple of)
the normal size of the local array’s emulation type (OPEN-3 in this example). Therefore, in this
example, the local array can realize two fully-sized OPEN-3 LDEVs, with some space (insufficient to
create a full OPEN-3) left over.
Figure 12 External LU capacity is larger than the specified emulation type’s basic capacity (OPEN-3
example)
Figure 13 shows an example where the external LU’s original capacity is smaller than the normal size
of the local array’s emulation type. In this example, since the resulting space is insufficient to create a
local array OPEN-3 LDEV, you can designate it as either a local array OPEN-V or an OPEN-3 CVS
LDEV. If the external LU were an XP of OPEN-3 emulation type, forfeiting a small amount of
management space would also result in an OPEN-3 CVS volume or an OPEN-V.
Figure 13 External LU capacity is smaller than the specified emulation type’s basic capacity
• IO Suppression mode can only be selected when the volume being mapped is set to the OPEN-V
emulation type. If a different emulation type is set, IO Suppression mode is automatically set to Disable.
• If you use the mapped external LU from the host connected to the local array, set the IO Suppression
mode to Disable when mapping the LU. For External Storage XP, select Disable. For Flex Copy XP, select
Enable.
• If you use the mapped external LU for the copy source or copy destination volume for a Flex Copy XP
pair, set the emulation type to OPEN-V when mapping the volume.
• If you use the mapped external LU for the copy source or copy destination volume for a Flex Copy XP
pair, set IO Suppression mode to Enable when mapping the volume.