IBM Systems Magazine, Mainframe Edition - May/June 2012 - (Page 31)

Tech Corner Programming, systems operations and more A New Performance Paradigm zHPF improves upon mainframe’s I/O capabilities By Harry Yudenfriend I IBM System z* High Performance FICON* (zHPF) is the most recent advance in optimizing mainframe I/O for storage devices. An open standard, the zHPF architecture has been adopted by all enterprise-class storage vendors for DASD attachment to System z10* and zEnterprise* servers. Over time, HBA vendors have added hardware assists that accelerate the execution of the Fiber Channel Protocol (FCP). However, z/OS technology requires support for the FICON protocol to deliver mainframe qualities of service and optimal execution of heritage software. A new I/O paradigm was required for System z to leverage hardware assists provided by HBA vendors. This new paradigm is zHPF. It provides a bilingual channel protocol to storage subsystems. Channels and control units implementing zHPF must also support FICON, which is required to support existing I/O programs (called channel programs) used by client applications and ISV products. FICON is also required for channel programs that use conditional execution and exploit the presentation of intermediate status, such as those using program controlled interrupts (PCIs). By dynamically choosing between zHPF and FICON, z/OS technology optimizes the execution of I/O requests. The zHPF open standard has been adopted by all enterprise-class vendors providing DASD storage for the mainframe. In its essence, zHPF leverages hardware assists provided by HBA vendors for the FCP transport while preserving enterprise-class qualities of service supported by FICON, including: Introduced in 2008 for the IBM DS8000* storage subsystem and System z10 servers with FICON Express4 channels, zHPF technology delivered several enhancements to transparently improve the performance and resilience of applications and middleware running on z/OS*. IBM has extended the value of the zHPF architecture to an increasing portion of z/OS workloads running on zHPF-capable hardware. What is zHPF? System z servers provide an infrastructure using standard I/O adapters, called host bus adapters (HBAs), for communicating over fiber channel (FC) storage area networks (SANs). This infrastructure provides robust hardware and system firmware to adapt the HBAs for the mainframe with the system assists needed to provide enterprise-class reliability, availability and serviceability (RAS). These assists help assure the server stability and data integrity transparently to the applications and middleware running on the server. hÁEnd-to-end data integrity checking, transparent to applications and middleware, between the System z processor and storage controller hÁIn-band I/O measurements to facilitate capacity planning, autonomic workload management, problem determination and data placement for the exploitation of storage tiers hÁEfficient, high-performance execution at a distance for two- and three-site configurations, including Geographically Dispersed Parallel Sysplex* (GDPS*) hÁAutonomic workload management for I/O (Intelligent Resource Director), including dynamic assignment of I/O priority, management of HyperPAV aliases, and dynamic throttling of I/O start rates and bandwidth with Dynamic channel path identifier (CHPID) management hÁRigorous I/O timeouts and timely detection of errors including lost frames hÁFairness for I/O resource sharing and application of I/O priorities hÁFirst failure data capture for quick, root-cause identification of failures that can disrupt the workload MAY/JUNE 2 012 31

Table of Contents for the Digital Edition of IBM Systems Magazine, Mainframe Edition - May/June 2012

IBM Systems Magazine, Mainframe Edition - May/June 2012
Table of Contents
Editor’s Desk: System z and Linux: The IT Odd Couple?
IBM Perspective: Opportunities Abound With Linux on System z
Insider: Virtualization Brings New Technology to Mainframe Tape
IT Today: What to Consider When Adding a Linux Workload to Your z/VM System
Cover Story: Better Together: Linux on System z gains followers as clients discover its performance and value
Features: Successes Mount for Linux on Mainframe: Usage patterns evolve, building value for organizations
Tech Corner: zHPF Improves Upon Mainframe's I/O Capabilities
Administrator: System Cryptography Capabilities Enable Linux Applications to Run Securely and Efficiently
Solutions/Advertisers Index: Attunity Replicate - ISPF MQ Message Editor for z/OS - Voltage SecureData z/Protect
Stop Run: Destination z Project Manager's Childhood Interest Leads to Impressive Collection
Reference Point
Special Supplement: Innovate 2012
Special Supplement: Services Blueprint: IBM Systems Lab Services and Training

IBM Systems Magazine, Mainframe Edition - May/June 2012