Enterprise IT staff are often tasked with updating their hardware and software, upgrading their application and database, installing new operating system versions, and performing system and datacenter migrations. All mission-critical teams must perform these operations without taking the application services offline. How can they accomplish this? With HPE Shadowbase Zero Downtime Migration (ZDM).
It is also a best practice that a disaster recovery copy of the database remains available and synchronized with the production database during the migration. Why? To preserve full business continuity protection throughout the migration; otherwise, the user takes tremendous risk if a disaster occurs during the migration.
If these requirements cannot be met, IT teams may be locked into an old, costly, or unsatisfactory solution. They may face an impossible situation, where potential costs of downtime and data loss are too great to risk making the change.
HPE Shadowbase ZDM offers solutions to these challenges. Migration projects can be undertaken without risk of application service outage or data loss, while preserving full business continuity coverage.
The old method of performing these operations is known as the Big-Bang approach. When implementing a Big-Bang approach, the production application and system are taken offline during a maintenance window, and the necessary changes are made. When the maintenance window closes, and the system and applications are brought back online, the new environment is put into service – ready or not.
Unfortunately, this approach is often unsuccessful due to limited testing time, constrained testing procedures, and complex and difficult failback if the new environment fails after the migration. Even worse, the new environment may run for some time before latent issues begin to emerge. When the failback occurs, newly created data is stranded in the new database, and it may be unrecoverable.
With HPE Shadowbase ZDM, applications and data remain available during the entire migration process, including during the switchover to the upgraded environment. If there is a problem in the new environment – either immediately or after the switchover – it is easy to switch back to the original production system with little or no interruption in services. More importantly, since Shadowbase software supports bi-directional data replication, the failback can be executed with zero data loss.
The HPE Shadowbase ZDM approach can be implemented on a single system or leveraged on two systems. However, these architectures are not best practice, since the same systems are used for production and migration.
Instead, a better practice is to leverage a three- or four-system architecture for the migration, because production is not affected or impacted until much later in the migration sequence. This practice also allows for comparing the data in the old environment to the data in the new environment to verify that it is correct, all before the application migration actually takes place.
The four-system architecture is often used for a platform refresh operation, leveraging two new systems for the migration, while the original production and backup runs uninterrupted.
With every HPE Shadowbase ZDM architecture, the new environment can be fully tested and verified for as long as necessary. The data can also be compared to validate consistency so that the migration is to a known-working system. Any discrepancies can then be repaired. This is the job of the HPE Shadowbase Compare and Repair solution.
The HPE Shadowbase ZDM approach works in active/passive, sizzling-hot-takeover, and active/active Shadowbase business continuity architectures.
It utilizes these HPE Shadowbase solutions to provide a seamless migration:
• data replication engine,
• online loading or SOLV utility,
• Compare and Repair, and
• SBMAP data transformation capabilities.
Hewlett Packard Enterprise globally sells and supports Shadowbase solutions under the name HPE Shadowbase. Specifications subject to change without notice. Trademarks mentioned are the property of their respective owners. Copyright 2022.