SQL Server Transaction Log Backup Errors

Common Transaction Log Failure Erros

• Make sure all databases in transaction log job are marked as Full backup.
• Make sure there is at least one successfully full database backup.
• Disable transaction log backup job when running a full database backup job.

Back up the log

Under the full recovery model or bulk-logged recovery model, if the transaction log has not been backed up recently, backup might be what is preventing log truncation. If the log has never been backed up, you must create two log backups to permit the Database Engine to truncate the log to the point of the last backup. Truncating the log frees space for new log records. To keep the log from filling up again, take log backups frequently.

Minimally, you must have created at least one full backup before you can create any log backups. After that, the transaction log can be backed up at any time unless the log is already being backed up.

We recommend you take log backups frequently, both to minimize work loss exposure and to truncate the transaction log.

Sources:

https://docs.microsoft.com/en-us/sql/relational-databases/logs/troubleshoot-a-full-transaction-log-sql-server-error-9002?view=sql-server-ver15

https://docs.microsoft.com/en-us/sql/relational-databases/backup-restore/transaction-log-backups-sql-server?view=sql-server-ver15