Mode Category Description Default
MCU/R
CU
also see spreadsheet "SOM897_898_901" for more details
about the relations between SOM897, 898 and 901.
908 Universal
Replicator
The mode can change CM capacity allocated to MPBs with
different workload.
Mode 908 = ON:
The difference in CM allocation capacity among MPBs with
different workload is large.
Mode 908 = OFF (default):
Difference in CM allocation capacity among MPBs with
different workload is small. (Existing operation)
Note:
1. If a CLPR is used by only some MPBs among all the
installed MPBs, set the mode to ON for the CLPR to
increase CM capacity allocated to the MPBs that use the
CLPR.
Example:
(a) A CLPR only for UR JNLG
(b) A configuration where MPBs and CLPRs are separately
used for open systems.
2, Since CM capacity allocated to MPBs with low load is
small, the performance is affected by a sudden increase in
load
3. This mode is effective for a CLPR. Therefore, when
setting the mode to ON/OFF, select target "LPRXX (XX=00
to 31)". For example, even when CLPR0 is defined (any of
CLPR1 to 31 are not defined), select “LPR00” first and
then set the mode to ON/OFF.
4. SOM908 cannot be used with SOM 933. When SOM 933
is set to ON, the function of SOM908 is canceled even
though SOM908 is ON.
OFF .
917 Dynamic
Provisioning,
Dynamic
Tiering
The mode is used to switch the method to migrate data at
rebalancing.
Mode 917 = ON (default):
Page usage rate is averaged among parity groups or
external volume groups where pool volumes are defined.
Mode 917 = OFF:
Page usage rate is averaged among pool volumes without
considering parity groups or external volume groups.
Note:
1. The mode is applied when multiple LDEVs are created
in a parity group or in an external volume group.
2. If the mode setting is changed during pool shrink, the
shrink processing may fail.
3. When the mode is set to OFF, the processing to the
average page usage rate among pool volumes in a
parity group or in an external volume group works;
therefore, the drive workload becomes high because
ON .
B-24
System option modes
Hitachi Unified Storage VM Block Module Hardware User Guide
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