Preparing for Universal Volume Manager Operations
3-9
Hitachi Universal Storage Platform V/VM Universal Volume Manager User’s Guide
VDEV
LDEV
LU
6 GB
Area provided to store data
management information
Free Space
(The area less than the basic
capacity of emulation type
remains as free space)
OPEN-3
External Volume
Figure 3-2
When the External Volume Capacity is Bigger than the
Basic Capacity of Specified Emulation Type (Example of
the OPEN-3 emulation type)
VDEV
LDEV
LU
External Volume
2 GB
Area provided to store data
management information
Figure 3-3
When the External Volume Capacity is Smaller than the
Basic Capacity of Specified Emulation Type
Guidelines for Mainframe Volumes
•
If you plan to use the mapped external volume from the mainframe OS
(e.g., the volume is mapped with the setting of 3390-x mainframe
emulation type), you need to select the external volume that consists of
one LDEV or you need to adjust the capacity of the external volume to be
mapped beforehand.
•
If multiple LDEVs exist in one external volume and if a lot of I/Os are made
to these LDEVs, the read, write commands may become timeout. When the
commands become timeout, the SIM (21D2xx) is reported.
