Mode Category Description Default
MCU/R
CU
Mode 855 = ON:
When the amount of dirty data is within the range from
58% to 63%, the next copy processing is continued after
the dirty data created in the previous copy is cleared to
prevent the amount of dirty data from increasing (copy
after destaging). If the amount of dirty data exceeds
63%, the copy processing is stopped.
Mode 855 = OFF (default):
The copy processing is stopped when the amount of dirty
data is over 60%.
Note:
1. This mode is applied when all the following conditions
are met
¢
ShadowImage is used with SOM 467 set to ON.
¢
Write pending rate of an MP blade that has LDEV
ownership of the copy target is high
¢
Usage rate of a parity group to which the copy
target LDEV belongs is low.
¢
ShadowImage copy progress is delayed.
2. This mode is available only when SOM467 is set to
ON.
3. If workload of the copy target parity group is high,
the copy processing may not be improved even if this
mode is set to ON
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 .
B-20
System option modes
Hitachi Unified Storage VM Block Module Hardware User Guide
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