New and old applications in a transition phase, it is essential when migrating data, then how to achieve the new and old systems coexist, is that many companies are very concerned about the team or, on the following scenario as an example to our actual, data migration considerations explained.
1. The data migration target
As business needs change, and constantly upgrading IT technology, the existing system will inevitably encounter some insurmountable limit, as the management of enterprises, in order to make the system better support business development, updating system replacement is inevitable, since the replacement, then to consider the business of the original data generated by the system can continue to provide value in the new system, the original system data needs to be migrated to the new system. Target data migration typically include standardization of data migration and data.
Data migration refers to the old system, business data and basic data migration to the new system, but due to the old and new systems for historical reasons, there are differences in the two systems is bound to data standards, such as the humble business of long growth companies establishment of a unified process platform, unified institutional users, a unified central authority, unified service centers, unified data center, then in addition to a previous part of the process does not require data to be processed, most of the data needs to be extracted, processed and Persistence. For example: the original user uses its own way, a user ID using the English name of the user, but the user unified mechanism used by the system are defined way of a combination of numbers and letters, the two systems are not compatible with the user.
The goal of building the new system, both to meet the needs of business growth, on the other hand also to meet enterprise unified planning, therefore, standardization of data is particularly important.
2. The range of data migration
After determining the goal of building a new system, we can consider the coexistence of old and new systems or data-dependent migration issues, a system has been running for many years, the data generated is very large, for the construction of a new operating system, those data migration is required, those things do not need to migrate, need to be clear before the data migration program to determine, for example: the new system uses a process platform, service bus platform, data bus platform, the platform for institutional users such as enterprise unified planning, then, migration data is generally not recommended to migrate data associated with specific technologies, such as: process data (most of the system construction, there are differences in the two sets of process engine, a huge migration of workload), but only part of the migration of business data and basic data .
This section needs to sort out the list of data migration, data migration strategy (incremental, full amount) and so on.
3. The data migration process
Data migration, is not easy, but need batches, data migration stages, such as: A first module and the migration module associated service data B, and the migration process, the migration of data is divided into four phases, the first read data and the standard data of the original system, the second stage of the read data is normalized, the third stage of the process a temporary table dump result, the fourth stage of the process of artificial loading data confirm and to the official repository.
Principle 4. Data Migration
New or upgrading old systems coexist, should follow certain rules or principles, as follows:
- All the data need to be migrated, before being loaded into a formal library, you must back up the official library;
- We need to migrate database should have the appropriate backup and recovery strategies;
- + Data extraction processing, prior to loading to the official database, there must manually confirm;
- The old and new system data migration, do not expect to pursue all of the data migration (the cost of enormous);
- Data migration tools, if conditional, try to use standard tools for migration;
The subsequent data migration
After the initial migration of data, be sure to verify all of the relevant functional data to avoid part of the data migration process, due to the new and old systems and standard formatting issues, cause the system to collapse Ben exception.