A backup that is performed while the database is in a read‑only state is referred to as a quiesced online, or warm, backup.
The database is placed in a quiescent state by allowing current active transactions to complete and then flushing modified buffers from cache to the stable database. In this mode, the physical database files contain all committed updates to the database and as the database files are opened with shared read access, external backup processes can safely copy the database files as a consistent database image.
During a quiesced backup, updating transactions are not permitted and attempts to execute database transactions raise an exception. When a backup is performed in a quiescent state, the physical database files are guaranteed to contain all database updates. Unlike a full online backup, a quiesced online backup does not require backup recovery when the database files are restored.
Use the JADE database administration framework to integrate online backup services into your applications or to build standalone database administration applications. Alternatively, the RootSchema provides a database backup service that you can incorporate directly into any of your applications. For details, see Chapter 7 of the JADE Developer's Reference.
The database files are verified while being read and optionally compressed while being written.
When a file backup completes, the MD5 checksum is automatically recomputed and compared with the value calculated when writing the file.
If you move database backups across media (for example, from disk to disk or tape to disk), it is essential that you verify the resulting files. Use the JADE Database utility