The IBM® HACMP software provides a low-cost commercial computing environment that ensures quick recovery of mission-critical applications from hardware and software failures. HACMP has two major components: high availability (HA) and cluster multi-processing (CMP). With HACMP software, critical resources remain available. For example, an HACMP cluster could run a database server program that services client applications. The clients send queries to the server program that responds to their requests by accessing a database, stored on a shared external disk. This high availability system combines custom software with industry-standard hardware to minimize downtime by quickly restoring services when a system, component, or application fails. Although not instantaneous, the restoration of service is rapid, usually within 30 to 300 seconds. In an HACMP cluster, to ensure the availability of these applications, the applications are put under HACMP control. HACMP takes measures to ensure that the applications remain available to client processes even if a component in a cluster fails. To ensure availability, in case of a component failure, HACMP moves the application (along with resources that ensure access to the application) to another.
High Availability is a key component of Business Resiliency. It's widely documented that outages increase the total cost of IT ownership as well as causing potential damage to client relationships and loss of revenue. Although hardware has become very reliable, research shows that unplanned outages occur and typically result from operator error, software bugs, environmental conditions and other non hardware related situations—problems that reliable hardware cannot prevent. Planned outages for application and system maintenance also impact business performance and businesses are aggressively shrinking the time allotted for this type of activity. Increasingly IT shops are moving away from outsourced DR operations to in-sourced DR operations based on continuous data replication between geographically dispersed locations. Modern DR solutions require both geographic dispersion and recovery point objectives as close to zero as possible. Increasingly, IT shops are being asked to prove that they can indeed recover operations at a remote facility. The simple fact is that owning your own DR solution is not only economically sensible but it gives you greater control over your environment. Finally, the IBM Power Systems™ strategy is to not only deliver more advanced functional capabilities for business resiliency but to enhance product usability and robustness through deep integration with AIX® and affiliated software stack technologies. PowerHA™ SystemMirror™ is architected by, developed by, integrated by, tested and supported by, IBM top to bottom.