Access to Data is Required 24×7
The demand for immediate, enterprise wide, 24×7 access to online data in support of new business services is ever-increasing. Consequently, so too are the demands placed on real-time data replication solutions. Data is needed everywhere, all the time.
With time, requirements change. Solutions that met yesterday’s business needs may not today, requiring a migration to a new solution with advanced data replication capabilities such as active/active business continuity as well as heterogeneous source/target database and platform architectures.
Switching to a modern, feature-rich data replication solution greatly benefits an enterprise. Data replication software enables a business to access important data in real-time, making smarter decisions based on relevant data. However, such a migration is not a straightforward “out with one; in with the other” process.
When planning a migration, remember:
- Significantly increased functionality brings more complexity
- Certain situations may be handled differently between replication solutions
Therefore, these migrations must be carefully planned and tested before implementation!
First, the “Replication Discovery” Process
In “replication discovery,” the current solution and its features are analyzed and relationships are drawn between current features and the new solution’s features. Any existing customizations, scripts, or custom code that is part of the solution must be documented.
Second, the “Roadmap” Process
Then, the team must map the existing features into those provided by the new solution. A roadmap is developed, describing the tasks needed to complete a migration. The roadmap must address situations that will require resolution (remediation) and include test plans to ensure that the new solution is smoothly implemented. Any pitfalls are explicitly named, analyzed, and addressed during the discovery, remediation, and testing process, long before the new solution goes into production.
Note: This process is iterative, since most customers are unfamiliar with the details, and the vendor’s professional services are required to help resolve any issues and ensure the solution successfully transitions from testing into production.
Typical HPE Shadowbase Zero Downtime Migration Options
Key Migration Considerations
Generally, copying the configuration for the current solution, applying it to the new solution, and forcing the new solution into production will not work. The different replication products have different configuration settings; there is generally not a simple 1:1 mapping between them. This approach would likely yield an unsuccessful migration, negatively affecting production.
Examples of key differences between products that must be identified and addressed in the Replication Discovery process are listed below.
- Replication architecture – each product has a different process architecture, for example, to:
- collect change data from the source database,
- store data in intermediate storage queues,
- apply change data to the target database,
- manage system operations, and
- report on status and activity.
It may be possible to mimic the current solution; yet, there may be benefits to implementing the new solution in a different replication architecture.
- Configuration – each product has unique configuration parameters, which should be tailored to best exploit the capabilities of the new solution. For example:
- Some replication products may automatically handle scalability, whereas others may require specific configuration parameters set to distribute workload and achieve scalability.
- The set of files/tables to be replicated also requires specification, etc.
- Special data types – there are a myriad of file/table data types and ways in which data may be addressed and manipulated. Generally, each replication solution handles these types in a similar way, but there may be specific situations where the semantics are different and require remediation when switching to the new solution.
- In practice, the data types, database schemas, and how applications are manipulating data need to be understood. Such situations must be identified and appropriately handled by the new solution.
- For example, in some cases for HPE NonStop entry-sequenced tables, the exact “Primary Key” SYSKEY will be preserved when replicated and applied to the target database; whereas in other cases, it will not be. Such cases need to be identified and resolved.
- Feature benefits – teams usually migrate to take advantage of new features, which are unavailable with the old solution. In this case, it would be counter-productive to simply “try and do things the old way.”
- Utilizing the enhanced capabilities of the new solution could yield great benefits.
- The team must identify how the new solution improves upon the current solution, increasing business value and improving the end user’s experience.
- Miscellaneous – other migration factors to consider will only be identified by completing the replication discovery step. The new solution vendor typically has experience performing migrations and is familiar with other factors to ensure a smooth, successful migration.
There are many benefits to migrating to a modern, feature-rich data replication solution. Such migrations are not a simple “rip and replace” – they need to be carefully planned. Successful migrations result from a thorough replication discovery process executed in partnership between the customer and the solution vendor. This process ensures that the migration and deployment into production is a success and that all the benefits of the new solution are leveraged; it should result in new business opportunities for the customer.
HPE Shadowbase Zero Downtime Migration (ZDM) software provides continuous availability, eliminates planned downtime (no application services downtime during the migration), and removes business risk from application upgrades. Hewlett Packard Enterprise globally sells and supports Shadowbase solutions under the name HPE Shadowbase.
For more information, please contact your local HPE Shadowbase representative or visit our website. For additional information, please view our Shadowbase solution videos: Vimeo.com/ShadowbaseSoftware.