XP10000 (HITA737-96003, March 2007)

HPAV for z/OS user guide for the XP128/XP1024/XP12000/XP10000 13

NOTE: If you will be using static HPAV, determine on which devices I/O requests are likely to converge,

and then assign more aliases to those base devices. If not, HPAV might not be able to provide much

improvement in host access to data in the XP1024/XP128/XP12000/XP10000.

Figure 1 Static HPAV

Dynamic HPAV

When dynamic HPAV is used, the number of aliases for a base device may change as the number of I/O

requests to the device changes. If I/O requests converge on several base devices, the number of aliases for

these devices may increase, while the number of aliases for other base devices may decrease. Dynamic

HPAV operations can balance workloads on base devices and optimize the speed for accessing data in

the XP1024/XP128/XP12000/XP10000.

The following figure shows an example of dynamic HPAV operations. Each of the three base devices (x10,

x11, and x12) was originally assigned two aliases. In this example, as I/O requests converge on base

device x10 (shown by the large arrow), the number of aliases for device x10 increases to four, while the

number of aliases for base device x11 and x12 decreases to one.