IBM PowerHA SystemMirror for IBM i

Since the first introduction of IBM® PowerHA® SystemMirror for IBM i in 2008, major global corporations have been transitioning from internal disk and logical replication to IBM storage servers and PowerHA SystemMirror for i. It’s not only the large corporations who take advantage of PowerHA; clients around the world with less than a terabyte of storage have also moved from logical replication environments to PowerHA with geomirroring.

PowerHA SystemMirror for i is the IBM Power Systems™ offering for high availability and disaster recovery. It’s an IBM storage-based clustering solution that is an integrated extension of the storage management architecture and the IBM i operating system. With a PowerHA cluster, you are able to deploy an HA solution that addresses both your storage requirements and high availability requirements with one integrated configuration that is both robust and easy to use.

PowerHA Cluster

A cluster is a collection of servers with a common set of shared data and management technology that provides IT operations with a single screen and a set of commands that enable the applications and data to be readily moved between nodes in the cluster for the purpose of mitigating the complexity and downtime time that can be associated with planned or unplanned outages.

A PowerHA cluster is created by taking the database out of SYSBAS and placing it into an Independent Storage Pool (IASP) and SYSBAS objects into the administrative domain. The data in the IASP is shared between the systems in the cluster. When configured into an IBM storage server, the IASP can be switched (LUN level switching) between partitions (nodes) in the cluster, and it can also be replicated to systems dispersed between remote locations. Replication via storage server is accomplished with Metro Mirror or Global Mirror; if one is using internal disk the technology is called geographic mirroring. The key to understanding this technology from a data resiliency perspective is that all of the data that paged out of main store to an IASP, including the local journals, is the data that is switched or replicated between nodes in the cluster. PowerHA is displacing logical replication environments world-wide because it directly addresses the problems of data synchro-nization, operational complexity and certainty of outcome that are the classic challenges associated with logical replication environments.

Once your PowerHA SystemMirror solution is deployed, there’s minimal IT operational involvement required. Not only is this a big savings in manpower, it is also peace of mind.

PowerHA SystemMirror for i Express Edition

New with IBM i 7.2 is the Express Edition. The Express Edition is designed to be the foundation for a class of HA/DR offerings based on restarting the LPAR into another LPAR on a different server for HA operations. The Express Edition differs from the Standard Edition in that the database is not placed into an IASP separate from SYSBAS. Rather, a primary LPAR is restarted or IPLd to a target LPAR on another server. With PowerHA 7.2 for i, the first stage of the Express Edition offering enables single node full system HyperSwap® with the DS8700 (and above) which provides customers with continu-ously available storage through either planned or unplanned storage events. With HyperSwap technologies, the act of moving between storage servers is nearly seamless.

PowerHA SystemMirror for i Standard Edition

The IBM PowerHA SystemMirror for i Standard Edition helps you to protect your critical business applications from outages in the data center (single-site solution), planned or unplanned.
The Standard Edition provides reliable monitoring, failure detection, and automated recovery of business application environments. It provides the capability to monitor various event sources such as the HMC, Power Systems, and storage server for a comprehensive list of errors, from hardware and network to application or environmental (i.e. power loss); enabling automated or operator initiated actions. Starting with IBM i 7.1 PowerHA SystemMirror Standard Edition supports LUN level switching for the DS8000, SVC and Storwize V3700, V5000 and V7000 family of storage servers.

PowerHA SystemMirror for i Enterprise Edition

The PowerHA SystemMirror for i Enterprise Edition includes all of the capabilities of the Standard Edition and more. The Enterprise Edition package enables you to extend your data center solution across up to three sites. PowerHA SystemMirror Enterprise Edition includes support for DS8000,SVC, V7000, V5000 and V3700 with either Metro Mirror or Global Mirror and with 7.1 of PowerHA SystemMirror, the Enterprise Edition also includes support for geomirroring asynchronous mode. Geographic mirroring synchronous mode support is included with the PowerHA SystemMirror Standard Edition.

Geographic mirroring is the IBM i host based mirroring over IP network solution that enables small clients to set up a geo-graphically dispersed two node PowerHA SystemMirror cluster using either internal or external disk. The geographic mirroring solution can lower your total cost of ownership in comparison to software replication options in both cost of acquisition and operational management costs. The introduction of geomirror async mode support with PowerHA SystemMirror 7.1 enables clients to extend the PowerHA SystemMirror cluster between sites with virtually unlimited distance. We recommend geomir-roring to be used for IASPs under 2 Tbytes.

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