ALTER SERVER AUDIT (Transact-SQL)

TO { FILE | APPLICATION_LOG | SECURITY }

Determines the location of the audit target. The options are a binary file, the Windows application log, or the Windows security log.

FILEPATH = 'os_file_path'

The path of the audit trail. The file name is generated based on the audit name and audit GUID.

MAXSIZE =max_size

Specifies the maximum size to which the audit file can grow. The max_size value must be an integer followed by MB, GB, TB, or UNLIMITED. The minimum size that you can specify for max_size is 2 MB and the maximum is 2,147,483,647 TB. When UNLIMITED is specified the file grows until the disk is full. Specifying a value lower than 2 MB will raise the error MSG_MAXSIZE_TOO_SMALL. The default value is UNLIMITED.

MAX_ROLLOVER_FILES =integer | UNLIMITED

Specifies the maximum number of files to retain in the file system. When the setting of MAX_ROLLOVER_FILES=0 there is no limit imposed on the number of rollover files that will be created. The default value is 0. The maximum number of files that can be specified is 2,147,483,647.

MAX_FILES =integer

Specifies the maximum number of audit files that can be created. Does not rollover to the first file when the limit is reached. When the MAX_FILES limit is reached, any action that causes additional audit events to be generated will fail with an error.

RESERVE_DISK_SPACE = { ON | OFF }

This option pre-allocates the file on the disk to the MAXSIZE value. Only applies if MAXSIZE is not equal to UNLIMITED. The default value is OFF.

QUEUE_DELAY =integer

Determines the time in milliseconds that can elapse before audit actions are forced to be processed. A value of 0 indicates synchronous delivery. The minimum settable query delay value is 1000 (1 second), which is the default. The maximum is 2,147,483,647 (2,147,483.647 seconds or 24 days, 20 hours, 31 minutes, 23.647 seconds). Specifying an invalid number will raise the error MSG_INVALID_QUEUE_DELAY.

ON_FAILURE = { CONTINUE | SHUTDOWN | FAIL_OPERATION}

Indicates whether the instance writing to the target should fail, continue, or stop if SQL Server cannot write to the audit log.

CONTINUE

SQL Server operations continue. Audit records are not retained. The audit continues to attempt to log events and will resume if the failure condition is resolved. Selecting the continue option can allow unaudited activity which could violate your security policies. Use this option, when continuing operation of the Database Engine is more important than maintaining a complete audit.

SHUTDOWN

Forces a server shut down when the server instance writing to the target cannot write data to the audit target. The login issuing this must have the SHUTDOWN permission. If the logon does not have this permission, this function will fail and an error message will be raised. No audited events occur. Use the option when an audit failure could compromise the security or integrity of the system.

FAIL_OPERATION

Database actions fail if they cause audited events. Actions which do not cause audited events can continue, but no audited events can occur. The audit continues to attempt to log events and will resume if the failure condition is resolved. Use this option when maintaining a complete audit is more important than full access to the Database Engine.

STATE = { ON | OFF }

Enables or disables the audit from collecting records. Changing the state of a running audit (from ON to OFF) creates an audit entry that the audit was stopped, the principal that stopped the audit, and the time the audit was stopped.

MODIFY NAME = new_audit_name

Changes the name of the audit. Cannot be used with any other option.

predicate_expression

Specifies the predicate expression used to determine if an event should be processed or not. Predicate expressions are limited to 3000 characters, which limits string arguments.

event_field_name

Is the name of the event field that identifies the predicate source. Audit fields are described in sys.fn_get_audit_file (Transact-SQL). All fields can be audited except file_name and audit_file_offset.

number

Is any numeric type including decimal. Limitations are the lack of available physical memory or a number that is too large to be represented as a 64-bit integer.

' string '

Either an ANSI or Unicode string as required by the predicate compare. No implicit string type conversion is performed for the predicate compare functions. Passing the wrong type results in an error.

You must specify at least one of the TO, WITH, or MODIFY NAME clauses when you call ALTER AUDIT.

You must set the state of an audit to the OFF option in order to make changes to an audit. If ALTER AUDIT is run when an audit is enabled with any options other than STATE=OFF, you will receive a MSG_NEED_AUDIT_DISABLED error message.

You can add, alter, and remove audit specifications without stopping an audit.

You cannot change an audit’s GUID after the audit has been created.

To create, alter, or drop a server audit principal, you must have ALTER ANY SERVER AUDIT or the CONTROL SERVER permission.

A. Changing a server audit name

USE master
GO
ALTER SERVER AUDIT HIPAA_Audit
WITH (STATE = OFF);
GO
ALTER SERVER AUDIT HIPAA_Audit
MODIFY NAME = HIPAA_Audit_Old;
GO
ALTER SERVER AUDIT HIPAA_Audit_Old
WITH (STATE = ON);
GO

B. Changing a server audit target

USE master
GO
ALTER SERVER AUDIT HIPAA_Audit
WITH (STATE = OFF);
GO
ALTER SERVER AUDIT HIPAA_Audit
TO FILE (FILEPATH ='\\SQLPROD_1\Audit\',
          MAXSIZE = 1000 MB,
          RESERVE_DISK_SPACE=OFF)
WITH (QUEUE_DELAY = 1000,
       ON_FAILURE = CONTINUE);
GO
ALTER SERVER AUDIT HIPAA_Audit
WITH (STATE = ON);
GO

C. Changing a server audit WHERE clause

ALTER SERVER AUDIT [FilterForSensitiveData] WITH (STATE = OFF)
GO
ALTER SERVER AUDIT [FilterForSensitiveData]
WHERE user_defined_event_id = 27;
GO
ALTER SERVER AUDIT [FilterForSensitiveData] WITH (STATE = ON);
GO

D. Removing a WHERE clause

ALTER SERVER AUDIT [FilterForSensitiveData] WITH (STATE = OFF)
GO
ALTER SERVER AUDIT [FilterForSensitiveData]
REMOVE WHERE;
GO
ALTER SERVER AUDIT [FilterForSensitiveData] WITH (STATE = ON);
GO

E. Renaming a server audit

ALTER SERVER AUDIT [FilterForSensitiveData] WITH (STATE = OFF)
GO
ALTER SERVER AUDIT [FilterForSensitiveData]
MODIFY NAME = AuditDataAccess;
GO
ALTER SERVER AUDIT [AuditDataAccess] WITH (STATE = ON);
GO

Reference

Concepts