B
Required Volume Capacity for each Emulation Type B-1
Hitachi Universal Storage Platform V/VM Universal Volume Manager User’s Guide
Required Volume Capacity for Each
Emulation Type
When you map an external volume as an internal volume, you need to specify
the emulation type for the mapped volume. The maximum capacity of an
external volume depends on the specified emulation type.
How to Figure Out Required External Volume Capacity
The capacity required for the LDEV to be mapped is the total capacity of the
data area for storing the actual user data and the control information area for
storing the 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 data area for Custom-sized Volume (CV) (called minimum data
area capacity) also depends on the emulation type. For detailed information
about the LDEV capacity for each emulation type, see Table B-2.
• You can calculate the minimum capacity required for an LDEV (minimum
LDEV capacity) for each emulation type using the following equation:
Minimum LDEV capacity = Minimum data area capacity + control
information area capacity
If the capacity of the external volume is less than this minimum LDEV
capacity, the emulation type cannot be specified.
• You can calculate the base LDEV capacity for each emulation type using the
following equation:
Base LDEV capacity = Base data area capacity + Control information
area capacity