IBM Systems Magazine, Mainframe Edition - March/April 2012 - 35

System z pushes the limits of high availability
By Dave Surman

S

ystem z* mainframes, along with z/OS* and its middleware stack, have earned a well-deserved reputation for industryleading reliability and high availability (HA). Each individual component— be it a hardware, firmware or software element within the system—is designed to be resilient. Many types of planned outages, such as planned maintenance, upgrades or configuration changes, are avoided through support for non-disruptive configuration changes and dynamic replacement capabilities. Unplanned outages are mostly avoided or their effects mitigated through robust support for recovery after a failure. This support can limit the scope of an outage’s impact, mask the effects completely or dynamically restart a failed element after an unrecoverable failure. Some time ago, it became apparent that no matter how robust an individual server or OS instance was, there would always be cases in which a hard failure of that single instance would result in the complete

unavailability of the business applications it hosts. No singlesystem solution could ever hope to avoid the “single point of failure” inherent in the system. To overcome this limitation, IBM designed and implemented the Parallel Sysplex* clustering solution for the mainframe. Today, it serves as the cornerstone of HA and continuous operations in most of the world’s large mainframe processing environments. The Parallel Sysplex solution creates a framework for replicating all of the major processing elements of a System z environment—including servers, OSs, middleware, applications, storage subsystems, connectivity and networking—to provide a highly redundant infrastructure with no single point of failure. In this multisystem environment, a common set of application data can be shared freely across these redundant servers and software images with dynamic routing capabilities. This enables the system to “float” service requests to elements providing good service and around elements performing less well.

HIGH AVAILABILITY AT A GLANCE
  For decades, IBM System z technology has been the industry leader in reliability and high availability (HA).   By creating a framework for replicating all major processing elements, the Parallel Sysplex clustering solution is the cornerstone of mainframe’s HA capabilities.   Recent Parallel Sysplex enhancements focus on handling “sick but not dead” conditions to address failures that don’t occur cleanly.   These enhancements include behavior modeling and failure prediction; integration of hardware and software reliability mechanisms; monitoring and avoiding “sick but not dead” conditions; and real-time, automated problem diagnostics.

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IBM Systems Magazine, Mainframe Edition - March/April 2012

Table of Contents for the Digital Edition of IBM Systems Magazine, Mainframe Edition - March/April 2012

IBM Systems Magazine, Mainframe Edition - March/April 2012
Table of Contents
Editor’s Desk: Rethinking System z
IBM Perspective: Smarter Computing, Enterprise Modernization and the Mainframe
Insider: Proper Tools Can Bring Flexibility to Application Development
IT Today: Six Things You Didn't Know About the Modern Mainframe
Trends: Seven Reasons IT Projects Fail
Cover Story: Agile Thinking: How to leverage existing technology to gain a competitive advantage
Features: All Together Now: A centralized business analytics environment delivers great value
Improving Upon the Gold Standard: System z pushes the limits of high availability
Tech Corner: Processor Design Innovations Empower the z196
Developer: Accurate Project Scoping Helps Map Out a Faster Route to Success
Solutions/Advertiser's Index: PASSPORT Host Integration Objects - LegaSuite 6
Stop Run: Mainframer Clarence Golson Reflects on a Diverse Career Built on a Single Platform
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Intro
IBM Systems Magazine, Mainframe Edition - March/April 2012 - IBM Systems Magazine, Mainframe Edition - March/April 2012
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Cover2
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 1
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Table of Contents
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 3
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 4
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 5
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Editor’s Desk: Rethinking System z
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 7
IBM Systems Magazine, Mainframe Edition - March/April 2012 - IBM Perspective: Smarter Computing, Enterprise Modernization and the Mainframe
IBM Systems Magazine, Mainframe Edition - March/April 2012 - I1
IBM Systems Magazine, Mainframe Edition - March/April 2012 - I2
IBM Systems Magazine, Mainframe Edition - March/April 2012 - I3
IBM Systems Magazine, Mainframe Edition - March/April 2012 - I4
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 9
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Insider: Proper Tools Can Bring Flexibility to Application Development
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 11
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 12
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 13
IBM Systems Magazine, Mainframe Edition - March/April 2012 - IT Today: Six Things You Didn't Know About the Modern Mainframe
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 15
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 16
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 17
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Trends: Seven Reasons IT Projects Fail
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 19
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 20
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 21
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 22
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 23
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Cover Story: Agile Thinking: How to leverage existing technology to gain a competitive advantage
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 25
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 26
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 27
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 28
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 29
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Features: All Together Now: A centralized business analytics environment delivers great value
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 31
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 32
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 33
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Improving Upon the Gold Standard: System z pushes the limits of high availability
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 35
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 36
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 37
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 38
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 39
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Tech Corner: Processor Design Innovations Empower the z196
IBM Systems Magazine, Mainframe Edition - March/April 2012 - V1
IBM Systems Magazine, Mainframe Edition - March/April 2012 - V2
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 41
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 42
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 43
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Developer: Accurate Project Scoping Helps Map Out a Faster Route to Success
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 45
IBM Systems Magazine, Mainframe Edition - March/April 2012 - 46
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Solutions/Advertiser's Index: PASSPORT Host Integration Objects - LegaSuite 6
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Stop Run: Mainframer Clarence Golson Reflects on a Diverse Career Built on a Single Platform
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Cover3
IBM Systems Magazine, Mainframe Edition - March/April 2012 - Cover4
IBM Systems Magazine, Mainframe Edition - March/April 2012 - RF1
IBM Systems Magazine, Mainframe Edition - March/April 2012 - BG1
IBM Systems Magazine, Mainframe Edition - March/April 2012 - BG2
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