HP StorageWorks External Storage XP user guide (T1706-96006, June 2006)

20 Preparing for External Storage XP operations
• Ports that can be set to external ports (see ”External ports” on page 20)
• External array and LUs to map to the internal LDEVs (see”External LU to be mapped” on page 20)
• Configuration of external LU groups (see ”External LU groups” on page 20)
• Configuration of external LU attributes (see ”External LU attributes set by mapping” on page 20)
• Configuration of alternate paths (see ”Alternate paths” on page 22)
External ports
Local array ports used for External Storage XP must be set to a designation of External. When the external
array is connected to the local array’s external port via Fibre Channel, you can view information about
the external array from Command View XP or XP Remote Web Console. The external array can be
connected only to ports designated as External.
To set the port attribute to External, you must release any existing paths currently configured for the port.
You cannot change the attribute of the port where paths are set to External. Before starting External
Storage XP operations, you must know which ports you can change to External.
NOTE: You cannot use ports with attributes set for remote copy software (such as RCU Target or Initiator)
or other features as external ports for External Storage XP. If the port attribute is set to something other
than External, change its attribute to External. Flex Copy XP and External Storage XP can share an
XP12000/XP10000/SVS200 port with an attribute of External.
For instructions, see ”Setting a local array’s port attributes” on page 72.
External LU to be mapped
When connecting an external array to an external port, you can map LUs in the external array (external
LUs) as LDEVs in the local array (internal LDEVs). Verify which LUs in which external array can be mapped
as internal LDEVs.
You can map only one external LU to a given internal LDEV and map up to a theoretical limit of 1,024
external LUs per local array port.
An external LU’s maximum available capacity depends on the emulation type set when the LU is mapped.
You cannot access data stored in the field over the external LU’s maximum available capacity. To set an
emulation type other than OPEN-V, you cannot map external LUs smaller than 38 MB (77,760 blocks). To
set the OPEN-V emulation type, you cannot map external LUs of smaller than 47 MB (96,000 blocks). For
more information about the capacity of the external LU for each emulation type, see ”Required volume
capacity for emulation types” on page 141.
External LU groups
When mapping an external LU as an internal LDEV, you must register the external LU in an external LU
group.
You can classify external LUs set by External Storage XP into groups according to their use. The group is
called an external LU group (ExG). For instance, you can register several LUs in one external array to one
external LU group. Or, if data you want to manage in a chunk is stored in LUs in various external arrays,
you can register those LUs in one external LU group, and manage them as a block.
You must assign a number from 1 to 16,384 to each external LU group. For the XP12000, you can create
a maximum of 15,360 external LU groups. For the XP10000/SVS200, you can create a maximum of
8,192 external LU groups. You can register a maximum of 256 volumes in one external group.
External LU attributes set by mapping
When mapping an external LU as an internal LDEV, use the Add LU pane in External Storage XP to set the
external LU’s attributes. For instructions, see ”Mapping external LUs (Add LU)” on page 73.
The following are the external LU’s attributes:
• Emulation type