User guide

System option modes B–21
Hitachi Unified Storage VM Block Module Hardware User Guide
803 Dynamic
Provisioning,
Data Retention
Utility
While a DP pool VOL is blocked, if a read or write I/O is
issued to the blocked pool VOL, this mode can enable the
Protect attribute of DRU for the target DP-VOL.
Mode 803 = ON:
While a DP pool VOL is blocked, if a read or write I/O is
issued to the blocked pool VOL, the DRU attribute is set
to Protect.
Mode 803 = OFF (default):
While a DP pool VOL is blocked, if a read or write I/O is
issued to the blocked pool VOL, the DRU attribute is not
set to Protect.
Note:
1. This mode is applied when
- a file system using DP pool VOLs is used.
- Data Retention Utility is installed.
2. Because the DRU attribute is set to Protect for the V-
VOL, a read I/O is also disabled.
3. If Data Retention Utility is not installed, the expected
effect cannot be achieved.
4. The Protect attribute of DRU for the HDP V-VOL can be
released on the Data Retention window of Storage
Navigator after recovering the blocked pool VOL.
OFF .
855 ShadowImage,
Volume
Migration
By switching the mode to ON/OFF when ShadowImage is
used with SOM 467 set to ON, copy processing is
continued or stopped as follows.
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
Mode Category Description Default
MCU/
RCU