Hitachi Virtual Storage Platform, Руководство пользователя и справочник

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Functional and Operational Characteristics
2–47
Hitachi VSP User and Reference Guide
897 Dynamic
Tiering,
Dynamic
Tiering for
Mainframe By the combination of SOM 897 and 898 setting, the
expansion width of Tier Range upper I/O value
(IOPH) can be changed as follows.
Mode 897 = ON :
SOM 898 is OFF: 110%+0IO
SOM 898 is ON: 110%+2IO
Mode 897 = OFF (Default)
SOM 898 is OFF: 110%+5IO (Default)
SOM 898 is ON: 110%+1IO
By setting the SOM s to ON to lower the upper limit
for each tier, the gray zone between other tiers
becomes narrow and the frequency of page
allocation increases.
Notes:
1. Apply the mode when the usage of upper tier is
low and that of lower tier is high.
2. The mode must be used with SOM 898.
3. Narrowing the gray zone increases the number
of pages to migrate between tiers per
relocation.
4. When Tier1 is SSD while SOM 901 is set to ON,
the effect of SOM 897 and 898 to the gray zone
of Tire1 and Tier2 is disabled and the SOM 901
setting is enabled instead. In addition, the
settings of SOM 897 and 898 are effective for
Tire2 and Tier3.
Please also see spreadsheet "SOM 897_898_901"
for more details about the relations between SOM
897, 898 and 901.
OFF ..
Mode Category Description Default MCU/RCU