Zero Downtime Migration / Sponsor

For many organisations, the focus is to deploy an interruption-free solution that runs old and new systems in parallel – if one system goes down, the other takes the full processing load. Active-active migrations, in which the user population is distributed between the target and source systems simultaneously, offer a solution which ensures synchronisation in a bi-directional fashion, with both upgrade and downgrade logic being applied in flight.



The bi-directional real-time movement of transactional data across two or more database instances allows organisations to increase availability SLAs and achieve this at a lower overall cost because all systems are active and available for processing. Even in complex and highly customised application environments, outages can be limited to the minutes or sometimes seconds required for application switchover to a synchronised, fully operational instance of the database.

Bidirectional synchronisation means loads can be distributed across multiple databases and servers where, in most cases, users can change the same sets of data, with software to synchronise those changes. However, SQL changes replicated from one system to another must be prevented from being replicated back to the first system again. Conflicts also have to be managed to ensure data integrity in the event that the same row is changed in two or more databases at (or about) the same time. One way this is achieved is through the use of custom conflict-resolution routines that satisfy complex business rules.

The bi-directional data movement in a dual-active database environment can also allow for phased migrations where users are pointed to either system (since both are live) and can be slowly "migrated over" to the new system once the new system is fully operational. Ultimately, as long as the user can access the data continuously and it is fully "intact", it should be business as usual with the job of the IT team being fully transparent.

Additionally, dual-active systems can easily cope with the spikes experienced during high volume transactional data processing and in this way the organisation can more easily scale to meet future growth.

One such example of an organisation using such an approach is Swedbank, one of the largest Nordic banks. It uses GoldenGate Software on an on-going basis to provide high availability for its payment processing systems. These run using ACI’s Base24 application running on HP Integrity servers. In the past the bank used a conventional hot standby system for failover and testing but the bank found that it always experienced delays when cutting over to the backup systems, whether for planned or unplanned outages. It therefore implemented an active-active solution from GoldenGate in order to ensure true continuous availability across all scenarios.

Today’s increasingly savvy customers want convenience and quality service, regardless of when, where or how they interact with an organisation. In these challenging times, failure to deliver against these expectations will be capitalised upon by the competition. When the focus is on retaining customers and building loyalty, delivering zero or near-zero downtime - especially during migration projects - is now a business imperative.

GoldenGate Software offers technology solutions for real-time capture, transformation, routing, delivery, and verification of data transactions across distributed, heterogeneous databases and platforms.

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