External Storage XP user guide 33
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 XP12000/XP10000 emulation type (OPEN-3 in this example). Therefore, in this
example, the XP12000/XP10000 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 capacity (OPEN-3 example)
Figure 13 shows an example where the external LU’s original capacity is smaller than the normal size
of the XP12000/XP10000 emulation type. In this example, since the resulting space is insufficient to
create an XP12000/XP10000 OPEN-3 LDEV, you can designate it as either an XP12000/XP10000
OPEN-V or as an “OPEN-3 CVS” LDEV. If the external LU were an XP of OPEN-3 emulation type, the
forfeiting of a small amount of management space would also result in either an “OPEN-3 CVS,”
XP12000/XP10000 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 set to Enable when the OPEN-V emulation type is set for the volume
being mapped. If a different emulation type is set, IO Suppression mode is set automatically to Disable.
• When accessing a mapped external LU from a host connected to the local disk array, set the IO
Suppression mode to Disable. 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 you map 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 you map the volume.
• The local disk array does not force the external disk array to reserve the mapped external LU. Therefore,
do not write directly to an external disk array LU (that is, without writing via the local XP disk array) with
IO Suppression mode set to Disable from the external disk array side.
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