Problem description
SQL Log backups fail with the error “INTERNAL 65535” accompanied by the entry 'No last log commit information available' in the detailed logs. This issue occurs specifically when backing up logs from a secondary node in a SQL Always On Availability Group (AAG) configuration.
Cause
When the backup preference is set to ‘secondary’ in an AAG configuration, the Hybrid workload agent for SQL performs the backup from the secondary node.
The failure occurs if a transaction log entry for the database is not found in msdb.dbo.backupset on that specific secondary node.
Traceback
To obtain the necessary logs, follow the instructions in the link below:
Extract the logs and open the Phoenix<YYYYMMDD>_<timestamp>.log file to locate the following error signature:
[ERROR] <_MainThread(MainThread)> Error <type 'exceptions.Exception'>:No current entry in backupset for [Instance_Name:DB_Name] for LOG backup type. Traceback -Traceback (most recent call last):
File "agents\sqlserver\VssHelper.pyc", line 723, in __is_log_chain_stable_for_ag
File "agents\sqlserver\sql_vss_2.pyc", line 177, in get_current_backupset_details
Exception: No current entry in backupset for [Instance_Name:DB_Name] for LOG backup type
[WARNING] <_MainThread(MainThread)> No Last log commit information available Instance_Name:DB_Name
[ERROR] <_MainThread(MainThread)> Unable to process database[DB_Name] for log backup: No last log commit information available[Instance_Name:DB_Name]
[ERROR] <_MainThread(MainThread)> Unable to discover databases for log backup: No last log commit information available[Instance_Name:DB_Name]
Resolution
To resolve this issue, you must establish a baseline backup on the node:
Run a manual backup for the affected SQL Backup Set using the ‘Backup Now’ option.
Verification
Monitor the manual backup triggered via 'Backup Now' to ensure it completes successfully.
Verify that subsequent scheduled log backups no longer trigger the "INTERNAL 65535" error.