Parallel Access Volumes In Dynamic Mode - HPE XP7 User Manual

controlled by the Dynamic alias management parameter setting for the IBM
and the WLMPAV parameter setting in the HCD file.
The XP7 Storage system uses the I-2107 control unit emulation. You can use one of the following modes:
• Dynamic Parallel Access Volumes mode
For more information about this mode, see Parallel Access Volumes in dynamic mode on page
7.
• Static Parallel Access Volumes mode
For more information about this mode, see Parallel Access Volumes in static mode on page 8.
• Hyper Parallel Access Volumes (HPAV) mode
You can specify the PAV feature (Parallel Access Volumes, Hyper Parallel Access Volumes, or
Compatible Super PAV) to use for each host computer. Therefore, an alias device may accept I/O
requests from PAV, HyperPAV, or SuperPAV.
For more information about this mode, see Hyper Parallel Access Volumes.
• Compatible Super PAV (Super PAV) mode
You can specify the PAV feature (Parallel Access Volumes,Hyper Parallel Access Volumes, or
Compatible Super PAV) to use for each host computer. Therefore, an alias device might accept I/O
requests from PAV, and I/O requests from HyperPAV and SuperPAV. For more information about this
mode, see Compatible Super PAV on page 9.
For more information:
• About WLM, see Workload Manager and Setting the WLM operational mode.
• About the WLMPAV parameter and HCD file, see Parallel Access Volumes in dynamic mode on
page 7.

Parallel Access Volumes in dynamic mode

In Parallel Access Volumes dynamic mode, the number of alias devices assigned to each base device
may dynamically increase or decrease based on the number of I/O requests to each device. Dynamic
mode assists in balancing workloads on base devices and can optimize the speed of accessing data in
the XP7 Storage. A dynamic Parallel Access Volumes operation is implemented when the WLM feature
for Dynamic alias management setting and the WLMPAV parameter setting in the HCD file are both set to
Yes.
For more information about setting the WLM operational mode, see Setting the WLM operational mode.
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.
®
Workload Manager
Parallel Access Volumes in dynamic mode
®
(WLM)
7