User guide

B–22 System option modes
Hitachi Unified Storage VM Block Module Hardware User Guide
857 OPEN This mode enables or disables to limit the cache
allocation capacity per MPB to within 128GB except for
cache residency.
Mode 857 = ON:
The cache allocation capacity is limited to within 128GB.
Mode 857 = OFF (default):
The cache allocation capacity is not limited to within
128GB.
Note:
This mode is applied when downgrading the micro-
program from V02 (70-02-02-00/00) or higher to a
version earlier than V02 (70-02-02-00/00) while over
128GB is allocated.
OFF -
867 Dynamic
Provisioning
All-page reclamation (discarding all mapping information
between DP pool and DP volumes) is executed in DP-VOL
LDEV format. This new method is enabled or disabled by
setting the mode to ON or OFF.
Mode 867 = ON:
LDEV format of the DP-VOL is performed with page
reclamation.
Mode 867 = OFF (default):
LDEV format of the HDP-VOL is performed with 0 data
writing.
Note:
1. This mode is applied at recovery after a pool failure.
2. Do not change the setting of the mode during DP-VOL
format.
3. If the setting of the mode is changed during DP-VOL
format, the change is not reflected to the format of the
DP-VOL being executed but the format continues in the
same method.
OFF .
872 Universal
Volume
Manager
When the mode is applied, the order of data transfer
slots is guaranteed at the destaging from VSP to an
external storage.
Mode 872 = ON:
The order of data transfer slots from VSP to an external
storage is guaranteed.
Mode 872 = OFF (default):
The order of data transfer slots from VSP to an external
storage is not guaranteed.
In V03 and later versions, the mode is set to ON before
shipment.
If the micro-program is exchanged to a supported
version (V03 or later), the setting is OFF as default and
needs to be set to ON manually.
Note:
1. This mode is applied when performance improvement
at sequential write in UVM configuration is required.
OFF .
Mode Category Description Default
MCU/
RCU