HP XP P9000 for Compatible PAV Software Licenses - Manual (Page 6)

Parallel Access Volumes in dynamic mode
When Parallel Access Volumes are in 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 P9500. 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.
In the following figure, the x10, x11, and x12 base devices were original 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 the base device x10 increases to four, while the
number of alias devices assigned to the base devices x11 and x12 decreases to one each.
Parallel Access Volumes in static mode
When Parallel Access Volumes are in static mode, the number of alias devices assigned to each
base device does not change, even when the number of I/O requests to each device changes. A
static 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 NO.
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 each base device does not change.
Workload Manager
The Workload Manager (WLM) is a software component of the MVS/ESA , z/OS, and OS/390
operating systems that enables the host computer to utilize Parallel Access Volumes.
The WLM manages workloads on MVS systems and has two operation modes to support dynamic
and static Parallel Access Volumes operations.
6 Overview