HP XP7 Storage - Manual (Page 6)

If you are operating the HP XP7 Storage system in I-2107 control unit emulation, you can use one
of the following modes:
•
Goal PAV mode
For more information about this mode, see (page 6) .
•
Compatibility PAV mode
For more information about this mode, see (page 7) .
•
Hyper Parallel Access Volumes (HPAV) mode
You can specify the PAV feature (PAV or HPAV) to use for each host computer. Therefore, an
alias device may accept I/O requests that you ran through PAV or HPAV.
For more information about this mode, see (page 7) .
For more information:
•
About WLM, see (page 7) and (page 22) .
•
About the WLMPAV parameter and HCD file, see (page 6) .
Goal mode
Goal mode assists in balancing workloads on PAV base devices and can optimize the speed of
accessing data in the HP XP7 Storage system. In goal mode, the number of alias devices assigned
to each PAV base device can dynamically increase or decrease based on the number of I/O
requests to each device.
To use dynamic PAV, set the WLM operational mode to goal mode. While in goal mode, the WLM
manages the system to meet a performance goal.
For more information about setting the WLM operational mode, see (page 22) .
In the following figure, the x10, x11, and x12 base devices were originally assigned two alias
devices each. In this example, as I/O requests converge on the base device x10 (indicated by the
large arrow), the number of alias devices for base device x10 increases to four, while the number
of alias devices assigned to the base devices x11 and x12 decreases to one each.
Implementing a dynamic PAV operation
Complete one of the following to implement a dynamic PAV operation:
•
In the WLM Service Coefficient/Service Definition Options screen, for Dynamic alias
management, select Yes.
For more information about this setting, see (page 22) .
•
In the HCD file, set the WLMPAV parameter to Yes.
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