RMS Journaling for OpenVMS helps maintain the data integrity of OpenVMS RMS files and protects this file data from becoming lost or inconsistent due to various failure scenarios. RMS Journaling for OpenVMS provides the following three methods of journaling:
- After-image (AI) journaling allows you to redo a series of modifications to a file. This type of journaling helps recover lost or corrupted files. After-image recovery restores the contents of the file from the point of the latest backup copy of that file.
- Before-image (BI) journaling allows you to undo a series of modifications to a file. This type of journaling returns the file to a previous known state. This is useful when a file is updated with erroneous data.
- Recovery unit (RU) journaling helps maintain transaction integrity, where a transaction consists of a group of related operations that must be atomic. That is, either all of the operations complete in their entirety, or none of the operations complete. This type of journaling helps prevent data from becoming inconsistent due to the incomplete execution of a transaction.
Journaling is applied on a file-by-file basis. A file can be marked for AI, BI, or RU journaling, or any combination of these methods. Within a given application, any combination of journaling methods can be used.
RMS Journaling for OpenVMS stores the information necessary for data recovery in files known as journals. Multiple files can use the same journal.
Integrity: HAOE, per active socket.