HP XP P9500 Owner's Manual page 48

Table 1 1 System option modes (continued)
Mode Category
901 Smart Tiers
Smart Tiers Z
904 Smart Tiers
Smart Tiers Z
908 Continuous Access
Journal
48 Functional and operational characteristics
Description
SOM899 is OFF: I/O synchronous copy starts when the number
of retries reaches half of the threshold of Auto LUN retry.
Mode 900 = OFF (default):
SOM899 is ON: I/O synchronous copy starts when the threshold
of Volume Migration retry is exceeded. (Recommended)
SOM899 is OFF: Volume Migration is retired and I/O
synchronous copy is not executed.
Note:
1. This mode is applied when improvement of Auto LUN success
rate is desired under the condition that there are many updates
to a migration source volume of Auto LUN.
2. During I/O synchronous copy, host I/O performance
degrades.
By setting the mode to ON or OFF, the page allocation method
of Tier Level ALL when the drive type of tier1 is SSD changes as
follows.
Mode 901 = ON:
For tier1 (drive type is SSD), pages are allocated until the capacity
reaches the limit. Without consideration of performance limitation
exceedance, allocation is done from highly loaded pages until
reaching the capacity limit
When the capacity of the tier1 reaches the threshold value, the
minimum value of the tier range is set to the starting value of the
lower IOPH zone, and the maximum value of the lower tier range
is set to the boundary value.
Mode 901 = OFF (default):
For tier1 (drive type is SSD), page allocation is performed based
on performance potential limitation. With consideration of
performance limitation exceedance, allocation is done from highly
loaded pages but at the point when the performance limitation
is reached, pages are not allocated any more even there is free
space.
When the capacity of the tier1 reaches the threshold value, the
minimum value of the tier range is set to the boundary value, and
the maximum value of the lower tier range is set to a value of
boundary value x 1 10% + 5 [IOPH].
By setting the mode to ON or OFF, the number of pages to be
migrated per unit time at tier relocation is changed.
Mode 904 = ON:
The number of pages to be migrated at tier relocation is set to
up to one page per second. Mode 904 = OFF (default):
No restriction on the number of pages to be migrated at tier
relocation (existing specification).
Notes:
1. This mode is applied when:
Smart Tiers Z is used (including multi platforms
configuration).
the requirement for response time is severe.
2. The number of pages to be migrated per unit time at tier
relocation decreases.
The mode can change CM capacity allocated to MPBs with
different workloads.
Mode 908 = ON:
Default MCU/RCU
OFF
OFF .
OFF .