Introduction
Maintaining continuous and consistent auditing is crucial for security, compliance, and troubleshooting. When working with SQL Server Always On Availability Groups, a failover event can pose significant challenges to your audit configurations and logs. This guide will help you navigate these challenges by outlining the key considerations and steps necessary to ensure that SQL Server auditing remains seamless during a failover.
Audit Configuration and Failover
Audit Configuration Consistency
Audit configurations (audit objects, server audit specifications, and database audit specifications) are not automatically synchronized across replicas. You must manually configure and enable the same audit settings on each replica before a failover occurs to ensure consistent auditing.
Audit Logs
Audit logs are stored where the audit target is defined (file, application log, or security log). During a failover, the new primary replica will use its own audit log settings and locations. Ensure that each replica has access to the same log storage location or a properly configured storage to maintain continuity.
Steps to Ensure Continuous Auditing During Failover
1. Pre-Failover Configuration
Manual Configuration:
Before any failover, ensure that the audit configurations are manually set up and enabled on all replicas. Use scripts to replicate the configurations across all replicas.
2. Verifying and Synchronizing Audit Settings
Script Audit Settings:
On the primary replica, script out the audit objects and specifications. Apply these scripts on all secondary replicas.
3. Failover Event
Post-Failover Check:
After a failover, the new primary replica (which was a secondary replica before the failover) should have the audit configurations already in place. Verify that the audit specifications are enabled on the new primary replica.
4. Continuous Monitoring
Regular Verification:
Periodically verify that audit configurations are consistent across all replicas. Ensure that audit logs are being captured correctly on the new primary replica after a failover.
Example Scenario: Manual Synchronization
On the Primary Replica:
Create and enable the necessary audit configurations using the following SQL script:
CREATE SERVER AUDIT [MyServerAudit]
TO FILE
( FILEPATH = 'C:\AuditLogs\' )
WITH
( QUEUE_DELAY = 1000,
ON_FAILURE = CONTINUE );
GO
CREATE SERVER AUDIT SPECIFICATION [MyServerAuditSpec]
FOR SERVER AUDIT [MyServerAudit]
ADD (FAILED_LOGIN_GROUP),
ADD (SUCCESSFUL_LOGIN_GROUP);
GO
ALTER SERVER AUDIT SPECIFICATION [MyServerAuditSpec] WITH (STATE = ON);
GO
USE [YourDatabase];
GO
CREATE DATABASE AUDIT SPECIFICATION [MyDatabaseAuditSpec]
FOR SERVER AUDIT [MyServerAudit]
ADD (SELECT ON DATABASE::[YourDatabase] BY [public]);
GO
ALTER DATABASE AUDIT SPECIFICATION [MyDatabaseAuditSpec] WITH (STATE = ON);
GO
Script Out the Configuration:
Right-click on the created audit objects and specifications, and select Script as > CREATE To > New Query Editor Window. Save these scripts for later use.
On the Secondary Replica:
Apply the saved scripts by connecting to the secondary replica and executing the scripts to create and enable the audit objects and specifications.
Post-Failover:
After a failover, connect to the new primary replica (previously a secondary) and verify that the audit specifications are enabled and audit logs are being written correctly.
Summary
To ensure that SQL Server auditing continues seamlessly during a failover in an Always On Availability Group, you must manually configure and synchronize the audit settings across all replicas before a failover. After a failover, verify that the new primary replica has the audit configurations enabled and is logging activities as expected. Regular monitoring and verification of audit settings and logs across replicas are crucial to maintaining a consistent and reliable auditing process.