Recovering the DS-System database
The DS-System is configured to perform a full database backup every day. However, you might need to recover the database in the event of a hard disk failure.
To restore the disk holding the log files:
1. Perform a full backup of the DS-System database (data files) immediately.
2. Replace the failed disk.
To restore the disk holding the data files:
1. Back up the current active transaction log.
2. Replace the failed disk.
3. Restore the most recent backup of the database without recovering the database.
4. If you perform other backups between two consecutive daily backups, do the following:
• If differential backups exist, restore the most recent one.
• Restore each transaction log backup created since the database or differential backup in the same sequence in which they were created without recovering the database.
NOTE: You can restore the database to the state it was at the point of failure if the current transaction log file for the database is available and not corrupted.
5. Apply the most recent log backup and recover the database.
If you restore from an older DS-System database dump, you might have the following issues:
• New or modified DS-Client and customer information since the dump time are lost.
• Activity logs and Event Logs since the dump time are lost.
• Reports since the dump time are lost.
• Potential libraries information since the dump time is lost. Libraries might not get reused and new library creation will take longer for some library files.
• Invalid library links may prevent synchronization of backups and this means no backup or restore for that particular set until the links are manually fixed.
• Used libraries might be marked as unused in the restore database. The Clean Library process will delete these files and the restore process for these files will fail. This error will not be detected during the next backup. To resolve this issue, run a full System Admin process.
• New library numbers will start with the last ID found in the database, potentially overwriting existing libraries and rendering restored data useless.
The loss of information described in the first five points does not affect the online files. The issue described in the last point would result in overwriting valid files with new ones. Restoring files linked to such libraries will retrieve completely different files and will fail because of a different signature, encryption or compression.
To address this issue, do the following:
• Whenever you restore the database from an older dump, you must update the information in the database with the current online storage before proceeding further. This process adds records to the database for all the libraries created after the dump. Synchronization is triggered when the DS-System service starts, if the db_number has a negative value from the ds_data table in the database. For example, if the db_number is 231, change it to –231.
• After you restore the database dump, but before you start the DS-System service, ensure you run the latest installation to apply the latest database patches. Also ensure the db_number field from the ds_data table in the database has a negative value.
NOTE: We recommend you run a full System Admin process as soon as the DS-System service starts.