HP XP7 Owner Guide (H6F56-96006)

Table 11 System option modes (continued)
MCU/RCUDefaultDescriptionCategoryMode
LDEV format of the DP-VOL is performed with page reclamation.
Mode 867 = OFF (default):LDEV format of the HDP-VOL is
performed with 0 data writing.
Notes:
1. 1. This mode is applied at recovery after a pool failure.
2. 2. Do not change the setting of the mode during DP-VOL
format.
3. 3. If the setting of the mode is changed during DP-VOL format,
the change is not reflected to the format of the DP-VOL being
executed but the format continues in the same method.
..OFFWhen the mode is applied, the order of data transfer slots is
guaranteed at the destaging from XP7 to an external storage.
External Storage872
Mode 872 = ON:
The order of data transfer slots from XP7 to an external storage
is guaranteed.
Mode 872 = OFF (default):
The order of data transfer slots from XP7 to an external storage
is not guaranteed.
In V03 and later versions, the mode is set to ON before shipment.
If the micro-program is exchanged to a supported version (V03
or later), the setting is OFF as default and needs to be set to ON
manually.
Note:
1. This mode is applied when performance improvement at
sequential write in UVM configuration is required.
OFFBy disabling context switch during data transfer, response time
in low I/O load is improved.
Mainframe894
Mode 894 = ON:
When all the following conditions are met, the context switch is
disabled during data transfer.
1. The average MP operating rate of MP PCB is less than 40 %,
or the MP operating rate is less than 50%.
2. Write pending rate is less than 35 %.
3. Data transfer length is within 8 KB.
4. The time from job initiation is within 1600 ?s
Mode 894 = OFF (default):
The context switch is enabled during data transfer.
Notes:
1. This mode is applied when improvement of I/O response
performance in low workload is required.
2. Because the processing on the Mainframe target port is
prioritized, other processing may take longer time compared
to that when the mode is set to OFF.
..OFFSetting the mode to ON or OFF, the link type with transfer speed
of 8 GBps or 4 GBps is reported respectively.
Continuous Access
Synchronous Z
895
Mode 895 = ON:
When the FICON/FC link up speed is 8 GBps, the link type with
transfer speed of 8 GBps is reported.
Mode 895 = OFF (default):
The link type with transfer speed of up to 4 GBps is reported ,
even when the actual transfer speed is 8 GBps.
System option modes, host modes, and host mode options 51