How to fix Error 1483 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 1483 – Database State Information (Hardened LSN / Commit LSN Mismatch)

Why This Error Happens

Error 1483 is an informational/diagnostic message that SQL Server logs when it reports the synchronization state of a database, specifically detailing the Hardened LSN (Log Sequence Number), Commit LSN, and Commit Time. This typically surfaces during Availability Group synchronization, database mirroring, or recovery operations when SQL Server is logging the exact point of log hardening to help diagnose data loss exposure or lag between the primary and secondary replicas. The underlying cause is usually a mismatch between how much log data has been hardened to disk (durably written) versus what has been committed, often due to I/O subsystem latency, network lag between AG replicas, or an abrupt failover/restart event.

Step-by-Step Resolution Guide

Step 1: Identify the Context of the Error in SQL Server Logs

  • Open SQL Server Error Log via SSMS (Management > SQL Server Logs) or check C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\Log\ERRORLOG on Windows Server 2025.
  • Note whether this appears during a failover, restart, or routine AG health check — this determines if it’s benign (informational) or indicative of a stall.
  • Cross-reference the timestamp with Windows Event Viewer (Application Log) for correlating disk or network warnings.

Step 2: Check Availability Group / Mirroring Health

  • Run the following query to inspect synchronization health:
SELECT ag.name, ar.replica_server_name, drs.synchronization_state_desc, 
drs.log_send_queue_size, drs.redo_queue_size
FROM sys.dm_hadr_database_replica_states drs
JOIN sys.availability_replicas ar ON drs.replica_id = ar.replica_id
JOIN sys.availability_groups ag ON ar.group_id = ag.group_id;
  • Look for high log_send_queue_size or redo_queue_size, which indicates the secondary cannot harden logs fast enough.
  • If the environment uses Synchronous Commit mode, verify network latency between replicas isn’t exceeding acceptable thresholds (ideally under 5ms round-trip).

Step 3: Validate Disk I/O and Storage Subsystem

  • Use Perfmon on Windows Server 2025 to monitor Avg. Disk sec/Write on the volume hosting the transaction log (.ldf) files.
  • Values consistently above 15-20ms indicate the storage is too slow to harden log records in time, directly causing the LSN gap reported in Error 1483.
  • If using virtualized storage (Hyper-V/Azure), confirm the virtual disk isn’t throttled and is using write-caching policies appropriate for SQL transaction logs.

Step 4: Review and Adjust the Endpoint/Mirroring Timeout Settings

  • If this error coincides with connection drops, check the mirroring endpoint timeout:
ALTER ENDPOINT [Hadr_endpoint] 
FOR DATABASE_MIRRORING (TIMEOUT = 30);
  • Ensure firewall rules on Windows Server 2025 aren’t dropping long-lived TCP connections on the Database Mirroring Endpoint port (commonly 5022).

Step 5: Apply Latest Cumulative Update

  • Navigate to Microsoft’s official download center and install the latest Cumulative Update (CU) for SQL Server 2025.
  • Restart the SQL Server service via services.msc or net stop MSSQLSERVER && net start MSSQLSERVER after patching to ensure the fix for LSN logging/reporting accuracy is applied.

Alternative or Verification Steps

  • Verify the Fix: Re-run the sys.dm_hadr_database_replica_states query from Step 2; confirm log_send_queue_size and redo_queue_size trend toward zero and remain stable under load.
  • Alternative Solution: If the Hardened LSN gap persists despite healthy network/disk metrics, temporarily switch the Availability Group to Asynchronous-Commit mode to isolate whether the issue is purely synchronous-commit latency versus an underlying storage corruption issue, then run DBCC CHECKDB on the affected database to rule out physical corruption.