PowerHA SystemMirror for i is an IBM offering for HA and DR on IBM i providing geographic mirroring capabilities with block storage replication over an IP connection, providing your database resides in an IASP (Independent Auxiliary Storage Pool). Due to this IASP pre-requisite, for some it can be complex to configure and requires confirmation from 3rd party vendors that they will maintain support for their solutions running in this configuration. In addition, if you have IBM partitions using just a system ASP or the system ASP plus ASPs 2-32, PowerHA cannot replicate these.
While PowerHA offers powerful resilience capabilities for IASP-housed objects it cannot replicate objects in the System ASP and instead provides an administrative domain function to monitor objects that can be found in *SYSBAS, synchronizing them to TARGET nodes in the PowerHA cluster. You may also find that you will need to write some code to interface with the administrative domain to automate some tasks that are intrinsic to software-based replication. Attributes that can be monitored in the administrative domain:
· Authorization lists (*AUTL)
· Classes (*CLS)
· Ethernet line descriptions (*ETHLIN)
· Independent disk pools device descriptions (*ASPDEV)
· Job descriptions (*JOBD)
· Network attributes (*NETA)
· Network server configuration for connection security (*NWSCFG)
· Network server configuration for remote systems (*NWSCFG)
· Network server configurations for service processors (*NWSCFG)
· Network server descriptions for iSCSI connections (*NWSD)
· Network server descriptions for integrated network servers (*NWSD)
· Network server storage spaces (*NWSSTG)
· Network server host adapter device descriptions (*NWSHDEV)
· Optical device descriptions (*OPTDEV)
· Printer device descriptions for LAN connections (*PRTDEV)
· Printer device descriptions for virtual connections (*PRTDEV)
· Subsystem descriptions (*SBSD)
· System environment variables (*ENVVAR)
· System values (*SYSVAL)
· Tape device descriptions (*TAPDEV)
· Token-ring line descriptions (*TRNLIN)
· TCP/IP attributes (*TCPA)
· User profiles (*USRPRF)
Any attributes outside of this list will need to be handled either manually or with the aid of a logical replication solution, such as Maxava for PowerHA.
PowerHA presents limitations in terms of data accessibility, confining data visibility exclusively to the node that holds ownership. Consequently, essential tasks like backups, reporting, and business intelligence are confined to the production server, potentially leading to resource strain and necessitating downtimes. However, an opportunity for enhanced flexibility emerges through the integration of PowerHA with software-based solutions.
By synergizing PowerHA with software-based tools, a new realm of possibilities unfolds. For instance, within the data center, PowerHA can be seamlessly paired with a software-driven logical replication tool. This combination enables the replication of data beyond the confines of the data center, making it possible to extend disaster recovery capabilities via a designated partition in co-location facilities or cloud environments. Added benefits also include the provision of data for backup, reporting, and business intelligence purposes.
Moreover, the strategic deployment of logical replication solutions, such as those provided by Maxava, in tandem with PowerHA, introduces an array of sophisticated capabilities. These capabilities surpass the confines of the administrative domain, offering a multifaceted landscape for addressing advanced requirements and intricate operational needs. The augmentation provided by Maxava's logical replication solutions further amplifies IBM i high availability and disaster recovery landscape.