This week’s blog was written by Jenny Dervin. Jenny is the technology leader for IBM i High Availability.
Last week, as part of the IBM i 7.1 TR6 announcement, we also announced several new enhancements to PowerHA SystemMirror for i. These enhancements will be available by the end of March via PTFs (SI48371, SI48522, and SI48540). All the changes will be available for the 7.1 release in every language currently supported by PowerHA.
Since PowerHA support for SAN Volume Controller (SVC) and Storwize V7000 replication services was made available last year, many customers have also requested LUN or logical unit switching for those storage devices. With the upcoming PTFs, PowerHA will support LUN level switching for the SVC, Storwize V7000, and Storwize 3700 storage devices. PowerHA LUN level switching support requires NPIV (N Port ID Virtualization) attachment of the storage device, and thus requires IBM i TR6.
With LUN level switching, access to a single IASP can be switched from one IBM i instance to another. This protects against planned or unplanned IBM i or Power systems outages. Since it does not protect against disk subsystem outages or disasters, the LUN level switching technology is commonly used in conjunction with a replication technology such as Metro Mirror or Global Mirror. While Metro Mirror and Global Mirror are not yet available on the Storwize V3700, the storage team has issued a statement of direction that support is coming.
Another PowerHA enhancement is the completion of support for all functionality within the PowerHA GUI. The PowerHA GUI was PTFed into 7.1 last year and supported a subset of the functionality within the PowerHA licensed product. Now, the PowerHA GUI will support all of the technologies available in the PowerHA product, including all of the enhancements available in March. The PowerHA GUI contains wizards to help in creating an IASP and moving libraries and directories into an IASP, as well as configuration and management capability for a hardware based replication solution. The PowerHA GUI is available as part of IBM Navigator for i.
A new ‘Work With’ command to manage administrative domain is available. The Work With Administrative Domain Monitored Resource Entries (WRKCADMRE) command will make it easier to manage a large number of monitored resource entries (MREs). The entries can be sorted by name, typeor status, and it’s also possible to position to specific MRE names or types.
There are other enhancements included in the PTFs as well. We’ve made usability and availability improvements to our administrative domain, FlashCopy, and replication functions to work from any cluster node. We’ve improved the availability of adding and removing administrative domain MREs. For our customers using the geographic mirroring technology, changing the synchronization priority is now less disruptive. For more information on these enhancements, as well as links to other PowerHA resources, go to the PowerHA developerWorks wiki.
To keep up-to-date with PowerHA enhancements as well as fixes, we now periodically update high availability PTF groups for both 6.1 and 7.1. The 6.1 PTF number is SF99606 and the 7.1 PTF number is SF99706. These latest enhancements will be included in the next 7.1 high availability PTF group refresh.