IBM Bolsters PowerHA with New Replication Options, GUI
October 24, 2011 Alex Woodie
One of the October 12 IBM announcements that we didn’t cover in last week’s The Four Hundred was new PRPQ features added to the PowerHA SystemMirror for i offering, which is IBM’s hardware-based disk clustering solution. IBM announced that PowerHA customers can now replicate data across additional external storage systems, including the Storwize V7000 midrange array and the SAN Volume Controller (SVC) appliance. PowerHA also got a new GUI and new command-line functionality.
PowerHA SystemMirror for i, in case you forgot, was officially unveiled as part of the IBM i 7.1 launch in April 2008, and is the follow-on product to the short-lived High Availability Solutions Manager (HASM) that IBM announced in January 2008. PowerHA makes extensive use of IBM’s independent auxiliary storage pool (iASP), clustering, and switched-disk technology, and uses various host-based and SAN-based replication methods–including Metro Mirror, Global Mirror, geographic mirroring (formerly referred to as cross-site mirroring, or XSM), and Flash Copy services–to move data between pairs of iASPs.
Under PowerHA, any iASP node in a cluster (including iASPs that are internal or external to the IBM i server) can be switched during a role swap, making the data available to other IBM i servers in the cluster. There’s a lot more to it than this, and while PowerHA may seem more complicated than traditional logical replication (which IBM continues to offer through its DataMirror iCluster offering), the basic underlying premise of making data pools switchable is actually simpler than full system mirroring, and more reliable in some circumstances. (The fact that some IBM i objects aren’t replicated via iASP technologies and need to be replicated logically led IBM to launch its HA Assist for i product in October 2009, but that’s another story.)
For the first three years of PowerHA availability, IBM supported the high-end DS8000 and midrange DS6000 line of storage arrays. This month, IBM announced that the full array of SAN-based PowerHA technologies, including Metro Mirror, Global Mirror, and FlashCopy services, are supported with the Storwize V7000 storage server and the SVC storage appliance. (Geographic mirroring is a host-based offering that keeps internal iASPs in synch and facilitates failovers, so it isn’t supported on any SAN arrays).
The Storwize V7000 storage array, which IBM announced a year ago, is a midrange disk array that houses SAS disks, features FC and SCSI connectivity, and holds as much as 240 TB of data when nine V7000s are strung together.
The SVC storage appliance, which gained IBM i support almost three years ago, uses virtualization to allow customers to connect SAN arrays from different vendors–including IBM’s Storwize V7000 and DS8800 arrays, EMC VMAX, Compellent Series 20 Storage Controller, and various Fujitsu Eternus arrays–and make them look like one giant array. Since small and medium-sized IBM i shops aren’t likely to run an array of SANs, the SVC is primarily an enterprise play.
IBM also delivered a new GUI interface for PowerHA that “makes configuration and management of a high availability environment easy to use and intuitively obvious,” the company says. The new GUI makes it easy to view the overall status of the HA environment, IBM says, and supports the capability to drill down to detect and correct specific problems. The software, which is a System Director Navigator plugin, supports host-based geographic mirroring and SAN-based mirroring.
Hardcore green-screen junkies who are allergic to colorful GUIs will appreciate the new command line option that IBM added to the product. The new command line enables users to create iASPs and configure geographic mirroring outside of the GUI.
IBM put the new PowerHA enhancements as a PRPQ, or Programming Request for Price Quote, which is an IBM mechanism for customers to request special functionality in their IBM products. Instead of delivering the enhancements on a one-off basis, IBM makes them available to the entire user community, but in some cases they may not be supported. This PRPQ carries its own product number, 5799-HAS, but doesn’t cost extra.
IBM offers two versions of PowerHA SystemMirror, including a Standard Edition and the Enterprise Edition. The Standard Edition will provide basic capabilities required for data center-level HA, including things like centralized cluster management, heartbeat monitoring, and failover. Large enterprises with multiple sites will be pointed toward the Enterprise Version, which includes the Metro Mirror, Global Mirror, Flash Copy, and Advanced Copy Services lab services capabilities that work with the DS6000, DS8000, Storwize V7000, and SVC storage products.
For more information on the PowerHA SystemMirror for i products, see www-03.ibm.com/systems/power/software/availability. For more information on the October 12 announcement, see IBM United States Software Announcement 211-411 (pdf).