Hitachi VSP G200 System Administration Manual page 372
Virtual storage platform gx00 and fx00
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Also See for VSP G200:
- User manual (326 pages) ,
- User and reference manual (531 pages) ,
- System administrator manual (368 pages)
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Mode
Category
899
Volume Migration In combination with the SOM 900 setting, this SOM
900
Volume Migration In combination with SOM 899 setting, this SOM determines
372
System Administrator Guide for VSP Gx00 models and VSP Fx00 models
Description
Mode 898 = ON:
•
SOM 897 is OFF: 110%+1IO
•
SOM 897 is ON: 110%+2IO
Mode 898 = OFF (default):
•
SOM 897 is OFF: 110%+5IO (default)
•
SOM 897 is ON: 110%+0IO
By setting the SOMs 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 this SOM when the usage of upper tier is low and
that of lower tier is high.
2.
This SOM must be used with SOM 897.
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 Tier1
and Tier2 is disabled and the SOM 901 setting is
enabled instead. In addition, the settings of SOM 897
and 898 are effective for Tier2 and Tier3.
For more details about the interactions between SOMs 897,
898, and 901, contact customer support (see
SOM897_898_901 sheet).
determines whether to execute and when to start the I/O
synchronous copy change as follows.
Mode 899 = ON:
•
SOM 900 is ON: I/O synchronous copy starts without
retrying Volume Migration.
•
SOM 900 is OFF: I/O synchronous copy starts when the
threshold of Volume Migration retry is exceeded.
(Recommended)
Mode 899 = OFF (default):
•
SOM 900 is ON: I/O synchronous copy starts when the
number of retries reaches half of the threshold of Volume
Migration retry.
•
SOM 900 is OFF: Volume Migration is retired and I/O
synchronous copy is not executed.
Notes:
1.
This SOM is applied when improvement of Volume
Migration success rate is desired under the condition
that there are many updates to a migration source
volume of Volume Migration.
2.
During I/O synchronous copy, host I/O performance
degrades.
whether to execute and when to start the I/O synchronous
copy change as follows.
Mode 900 = ON:
System option modes
Default
MCU/RCU
OFF
-
OFF
-
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