HP StorageWorks External Storage XP user guide (December 2005)

20 External Storage XP for the XP10000/XP12000
Using existing data in mapped external LUs
NOTE: With the exception of MSA, a host can directly access external disk array volumes that are not
mapped as local disk array volumes.
Figure 10 Using existing data in mapped external LUs (without formatting)
Figure 10 shows an example of using existing data in a mapped external LU from the host connected to the
local disk array. In this case, use the following procedure:
1. From a host connected directly to the external disk array, write data to the LU in the external disk array.
2. Use External Storage XP to map the LU in the external disk array containing data as an internal XP
LDEV of the local disk array.
When mapping the external LU, set the following attributes for the mapped LU:
• Emulation type: OPEN-V
• IO Suppression mode: Disable
For more information, see ”Mapping external LUs” on page 45.
NOTE: To read existing data in the mapped external LU using the local disk array, set the
emulation type to OPEN-V. Other emulation modes require that the data space be resized, which in
effect destroys existing data. Once an external LU is mapped to the local disk array for use by
External Storage XP, direct host access to that LU is no longer allowed. Also set the emulation type
to OPEN-V when the VMA of LUN Security XP Extension is set for the external volume on the
external disk array side.
3. Configure the path from the Target port to the mapped LU. The mapped LU is available for host I/O
operations.
NOTE: Do not access any external storage volume that is mapped as an External Storage XP volume from
a host connected directly to the external disk array. Also, do not access an External Storage XP mapped
external array volume using the external disk array’s functions (for example, local replication). After
mapping an external disk volume as a local XP10000/XP12000 volume, access the mapped external
disk volume only via the local XP10000/XP12000 disk array.