Hitachi VSP User and Reference Guide
2–46
Functional and Operational Characteristics
896 Dynamic
Provisioning
Dynamic
Provisioning
for Mainframe,
Dynamic
Tiering
Dynamic
Tiering for
Mainframe,
Hitachi Thin
Image
The mode enables or disables the background
format function performed on an unformatted area
of a HDP/HDT pool.
For the information of operating conditions, refer to
Provisioning Guide for Open Systems or
Provisioning Guide for Mainframe Systems.
Mode 896 = ON:
The background format function is enabled.
Mode 896 = OFF (default):
The background format function is disabled.
Note:
1. The mode is applied when a customer requires
the background format for a DP/HDT pool in the
environment where new page allocation (for
example, when system files are created from a
host for newly created multiple HDP VOLs),
frequently occurs and the write performance
degrades because of an increase in write
pending rate.
2. When the mode is set to ON, because up to
42MB/s of ECCG performance is used, local
copy performance may degrade by about 10%.
Therefore, confirm whether the 10%
performance degradation is acceptable or not
before setting the mode to ON.
3. When a Dynamic Provisioning VOL that is used
as an external VOL is used as a pool VOL, if the
external pool becomes full due to the
background format, the external VOL may be
blocked.
If the external pool capacity is smaller than the
external VOL (Dynamic Provisioning VOL), do
not set the mode to ON.
OFF ..
Mode Category Description Default MCU/RCU
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