HP StorageWorks XP Remote Web Console Software User Manual
Page 218
218 Hitachi TrueCopy z/OS for HP XP12000/XP10000 and SVS 200 storage systems
•
The operating system must support the new DONOTBLOCK option.
•
Mode 61 must be ON.
If Mode 61 is OFF (default), the XP12000/XP10000 performs current load balancing control. If the
operating system does not support the DONOTBLOCK option, set Mode 61 = OFF.
DONOTBLOCK option: The XP12000/XP10000 does not block write I/Os for the specified logical device,
to avoid performance impact for application programs.
CAUTION:
If you specify the DONOTBLOCK option for too many devices, a sidefile puncture condition
will occur. Use caution when determining the appropriate tuning (devices with DONOTBLOCK option, SVP
modes) for your operational environment.
Load balancing control for sidefile: When the DONOTBLOCK option is not specified, the
XP12000/XP10000 has four levels of load balancing for amount of sidefile. Level 0 control is new for load
balancing control.
•
Level 0: Sidefile capacity is less than threshold 1 in the total cache capacity.
MODE 45 = ON: Write I/Os for logical devices are blocked (“Sleep”-“Wait” logic) by the threshold
(500 HEX RECSETS) specified by SDM.
MODE 45 = OFF: Write I/Os are not blocked.
•
Level 1: Sidefile capacity is over threshold 1 - threshold 2 of the total cache capacity.
MODE 97: “Wait” timer control. Same as level 1 in current load balancing control.
•
Level 2: Sidefile capacity is over threshold 2 - threshold 3 of the total cache capacity.
MODE 98: “SCP” reporting suppression option. Same as level 2 in current load balancing control.
•
Level 3: Sidefile capacity exceeds threshold 3 of the total cache capacity. Sidefile puncture occurs.
Same as level 3 in current load balancing control.
Variable sidefile threshold. Two new system options are assigned as variable sidefile threshold as follows.
These options are effective whether Mode 61 = ON or OFF.
•
MODE 85, 86
• Combination 1: MODE 85,86 = ON,OFF – Threshold 1/2/3=30/40/50%
• Combination 2: MODE 85,86 = OFF,OFF – Threshold 1/2/3=40/50/60% Default
• Combination 3: MODE 85,86 = OFF,ON – Threshold 1/2/3=50/60/70%