IBM Systems Magazine, Mainframe Edition - March/April 2012 - 36

Using the Parallel Sysplex solution, planned outages for disruptive single-system changes can be rolled through the configuration by taking down one system or middleware instance at a time without impacting the overall availability of the application or its data. Similarly, unplanned outages that result in the failure of a single system or middleware instance often can be recovered without affecting the application or data. The combination of system recovery and failover with dynamic workload routing is designed to let the surviving elements in the sysplex assume the responsibility for processing the work of failed elements. With the Parallel Sysplex foundation firmly established, what new frontiers and directions are being pursued to take System z resiliency to the next level? Let’s look at some recent developments in this area.

hÁReacquire locks held by the
failed element hÁPerform transactional recovery to either back out or complete work that was in progress on the failed element hÁRestart the failed element to run elsewhere However, problems do not always exhibit this orderly failure behavior. Instead of an element failing cleanly, it might linger in a hung, looping or unresponsive state in which other elements still see it as being operational and continue to route work to it. Recent enhancements in the Parallel Sysplex solution have focused on improving the handling of such “sick but not dead” conditions in a variety of different contexts. In a sysplex, z/OS interacts extensively with middleware to coordinate processing between the instances of middleware hosting the application workload. Monitoring has been added to many of these interactions, looking for evidence of a rogue middleware instance and searching for time-outs, hangs, or incorrect responses or processing. Under the control of the sysplex failure management (SFM) component of z/OS, the OS can declare such unresponsive-looking

Parallel Sysplex Enhancements Recovery in a Parallel Sysplex environment often hinges on knowing with certainty an element has failed or been deliberately removed, therefore making it physically unable to process shared data. When this is known, surviving systems in the environment can:

middleware instances—or even entire OS instances—to be “dead” and take the necessary termination actions to ensure they actually are dead so that sysplex recovery actions can safely be taken while preserving the integrity of shared data. A significant aspect of this monitoring capability involves SFM exploiting System z hardware management interfaces to query the physical states of remote servers and LPARs through the hardware management network whenever it appears that one of these servers or LPARs has become unresponsive. Often, this allows SFM to determine that an unresponsive system is on a server or LPAR in which processing is impossible, such as when it’s powered off, reset, re-IPLed or in a disabled-wait state. Thereby, SFM infers the system can be immediately removed from the sysplex and recovery actions driven. SFM can also use these hardware management interfaces to reset an unresponsive image, again with the goal of making it eligible for immediate removal, so surviving systems can continue processing the workload.

Predictive Failure Analysis Some problems build up gradually over time before they manifest actual symptoms. A classic example is the

PFA capability warns the installation before problems become symptomatic.
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MARCH/APRIL 2012 ibmsystemsmag.com/mainframe


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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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