## 6.2.2 Synergy with IBM Z 

The DS8000 is able to work in cooperation with IBM Z to provide several performance enhancement functions. The following section gives a brief overview of these synergy items. 

## Parallel access volume and HyperPAV 

Parallel access volume (PAV) is included in the DS8000 z-Synergy Services license group, for the z/OS and z/VM operating systems. With PAV, you can run multiple I/O requests to a volume at the same time. With dynamic PAV, the z/OS Workload Manager (WLM) controls the assignment of alias addresses to base addresses. The number of alias addresses defines the parallelism of I/Os to a volume. HyperPAV is an extension to PAV where any alias address from a pool of addresses can be used to drive the I/O, without WLM involvement. 

## Cross Control Unit PAV or SuperPAV 

With later DS8880 generations, HyperPAV had been enhanced further. If all alias addresses are busy, z/OS can now use an alias address from another logical control unit (LCU), providing these conditions are met: 

GLYPH<SM590000> The alias devices are assigned to the same DS8000 server (odd or even LSS) 

GLYPH<SM590000> The alias devices share a path group on the z/OS host 

The system now has a lager pool of alias addresses for bursts of I/O to a base volume and thus reduce queuing of I/O. This feature is known as Cross-CU PAV or SuperPAV. See “SuperPAV” on page 111. 

## Easy Tier support 

IBM Easy Tier is an intelligent data placement algorithm in the DS8000 that is designed to support both open systems and IBM Z workloads. 

Specifically for IBM Z, IBM Easy Tier provides an application programming interface (API) through which IBM Z applications (zDb2 initially) can communicate performance requirements for optimal data set placement. The application hints set the intent, and Easy Tier then moves the data set to the correct tier. For more information, see 6.6, “IBM Easy Tier” on page 172. 

## Extended Address Volumes 

This capability can help relieve address constraints to support large storage capacity needs by addressing the capability of IBM Z environments to support volumes that can scale up to approximately 1 TB (1,182,006 cylinders). 

## High Performance FICON for IBM Z 

High Performance FICON for IBM Z (zHPF) is an enhancement of the FICON channel architecture. You can reduce the impact of FICON channel I/O traffic by using zHPF with the FICON channel, the z/OS operating system, and the storage system. zHPF allows the storage system to stream the data for multiple commands into a single data transfer section for I/Os that are initiated by various access methods, This process improves the channel throughput on small block transfers. 

zHPF is an optional feature of the DS8900, included in the z-Synergy Services license group. Recent enhancements to zHPF include Extended Distance capability, zHPF List Pre-fetch, Format Write, and zHPF support for sequential access methods. 

