HPE Shadowbase replication requires that the Enscribe files and SQL tables be TMF-audited while replicating database changes on HPE NonStop platforms. All changes made to the data must be captured by HPE NonStop TMF in the context of application delimited transactions (BeginTransaction, do work, EndTransaction), and logged to the TMF audit trail. HPE Shadowbase software then reads these changes from the TMF audit trail for replication.
But what if the data required to be replicated by Shadowbase technology is not audited? There are a few solutions:
HPE NonStop AutoTMF is a product available from HPE which utilizes non-intrusive intercept technology to automatically invoke TMF transaction protection for applications that do not use TMF when updating data files. This technology enables non-audited applications running on a NonStop system to access and create audited Enscribe files without program modification or recompilation.
AutoTMF software dynamically determines effective and efficient TMF transaction boundaries and automatically consolidates multiple database updates, ensuring low overhead. There is no need to make any source code changes to programs, or even to recompile them, since AutoTMF works with your existing application object files. AutoTMF–enabled applications also benefit from the performance optimization of audited operations, such as advanced file buffering, and elimination of the block-splitting overhead associated with insertions to a file.
By using AutoTMF, users can quickly and easily enable TMF auditing for their data, so it can be readily replicated by Shadowbase replication. Once AutoTMF is installed and configured for your applications, you can turn the TMF audit file/table attribute on, and all subsequent file/table operations will be captured by TMF and can then be replicated by Shadowbase technology.
Figure 1 illustrates the architecture for HPE Shadowbase File Chaser, also known as HPE Shadowbase SOLV Manager (SOLVMGR). SOLVMGR is used when an application makes database changes to non-audited Enscribe files and SQL tables, and generates log files of these changes (business transaction data). The SOLVMGR periodically launches SOLV loaders, which read the log files forwards from a saved Restart Point as each successive SOLV loader runs. This step allows for optional and periodical transformation and maintenance of the application-generated log files/tables. The SOLV loaders inject the log data into the replication stream, which are made available to any Shadowbase target environment/data replication system for processing.
HPE Shadowbase File Chaser as shown in Figure 1 is a component of the Shadowbase SOLV loading utility that enables replication to the changes being made to certain non-audited Enscribe files and SQL tables.
For applications that do (or could be made to) create and maintain their own non-audited log files/tables, Shadowbase File Chaser reads these application-generated log files/tables, optionally transforms the events, and injects the events into the replication stream to the target environment, as the application appends data to the files/tables. This technique avoids the need for the source database to be audited while helping to ensure that such changes are also replicated.
During configuration, the Shadowbase File Chaser can be given a range of sub-volumes and application maintained files/tables to monitor for changes. This is useful, for example, when the application creates a sequenced list of log files and periodically rolls through them as it fills them. As the application appends change-data into these log files/tables, Shadowbase File Chaser will see those changes, and periodically read/inject them into the Shadowbase data replication engine for processing.
HPE Shadowbase SOLV Snapshot Loading, also known as HPE Shadowbase point-in-time loading, as shown in Figure 2 is a technique for reading and replicating TMF-audited or non-audited source Enscribe files and SQL tables to a target environment. When the source file/table is audited, the Shadowbase data replication engine can then replicate subsequent changes made to the source file or table to the target environment. When the source file/table is non-audited, the Shadowbase engine will not see the subsequent changes made to the source file or table (as they do not appear in the TMF audit trail), hence creating a snap-shot point-in-time copy of the source file/table on the target. To pick up subsequent changes made to the non-audited source file or table, another SOLV Snapshot Load would need to be run.
HPE NonStop AutoSYNC is a product available from HPE which replicates non-database files such as program object code files, command scripts, OBEY files, etc., to a target environment, usually for business continuity purposes. It can be configured to periodically check for files that need to be replicated so that the target will always have an up-to-date copy in case of failover.
AutoSYNC is a powerful addition to a business continuity solution when non-database files need to be replicated. For more information about HPE NonStop AutoSYNC, visit the HPE NonStop Business Continuity Product Suite.