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CREATE SERVER AUDIT (Transact-SQL)

Creates a server audit object using SQL Server Audit. For more information, see SQL Server Audit (Database Engine).

Applies to: SQL Server (SQL Server 2008 through current version).

Topic link icon Transact-SQL Syntax Conventions

CREATE SERVER AUDIT audit_name
{
    TO { [ FILE (<file_options> [ , ...n ] ) ] | APPLICATION_LOG | SECURITY_LOG }
    [ WITH ( <audit_options> [ , ...n ] ) ] 
    [ WHERE <predicate_expression> ]
}
[ ; ]

<file_options>::=
{
        FILEPATH = 'os_file_path'
    [ , MAXSIZE = { max_size { MB | GB | TB } | UNLIMITED } ]
    [ , { MAX_ROLLOVER_FILES = { integer | UNLIMITED } } | { MAX_FILES = integer } ]
    [ , RESERVE_DISK_SPACE = { ON | OFF } ] 
}

<audit_options>::=
{
    [   QUEUE_DELAY = integer ]
    [ , ON_FAILURE = { CONTINUE | SHUTDOWN | FAIL_OPERATION } ]
    [ , AUDIT_GUID = uniqueidentifier ]
}

<predicate_expression>::=
{
    [NOT ] <predicate_factor> 
    [ { AND | OR } [NOT ] { <predicate_factor> } ] 
    [,...n ]
}

<predicate_factor>::= 
    event_field_name { = | < > | ! = | > | > = | < | < = } { number | ' string ' }

TO { FILE | APPLICATION_LOG | SECURITY_LOG }

Determines the location of the audit target. The options are a binary file, The Windows Application log, or the Windows Security log. SQL Server cannot write to the Windows Security log without configuring additional settings in Windows. For more information, see Write SQL Server Audit Events to the Security Log.

FILEPATH ='os_file_path'

The path of the audit log. 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. (0 also indicates UNLIMITED.) 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 in addition to the current file. The MAX_ROLLOVER_FILES value must be an integer or UNLIMITED. The default value is UNLIMITED. This parameter is evaluated whenever the audit restarts (which can happen when the instance of the Database Engine restarts or when the audit is turned off and then on again) or when a new file is needed because the MAXSIZE has been reached. When MAX_ROLLOVER_FILES is evaluated, if the number of files exceeds the MAX_ROLLOVER_FILES setting, the oldest file is deleted. As a result, when the setting of MAX_ROLLOVER_FILES is 0 a new file is created each time the MAX_ROLLOVER_FILES setting is evaluated. Only one file is automatically deleted when MAX_ROLLOVER_FILES setting is evaluated, so when the value of MAX_ROLLOVER_FILES is decreased, the number of files will not shrink unless old files are manually deleted. The maximum number of files that can be specified is 2,147,483,647.

MAX_FILES =integer

Applies to: SQL Server 2012 through SQL Server 2014.

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. It applies only 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 SQL Server if the target cannot write to the audit log. The default value is CONTINUE.

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.

AUDIT_GUID =uniqueidentifier

To support scenarios such as database mirroring, an audit needs a specific GUID that matches the GUID found in the mirrored database. The GUID cannot be modified after the audit has been created.

predicate_expression

Applies to: SQL Server 2012 through SQL Server 2014.

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

Applies to: SQL Server 2012 through SQL Server 2014.

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

Applies to: SQL Server 2012 through SQL Server 2014.

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 '

Applies to: SQL Server 2012 through SQL Server 2014.

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.

When a server audit is created, it is in a disabled state.

The CREATE SERVER AUDIT statement is in a transaction's scope. If the transaction is rolled back, the statement is also rolled back.

To create, alter, or drop a server audit, principals require the ALTER ANY SERVER AUDIT or the CONTROL SERVER permission.

When you are saving audit information to a file, to help prevent tampering, restrict access to the file location.

A. Creating a server audit with a file target

The following example creates a server audit called HIPPA_Audit with a binary file as the target and no options.

CREATE SERVER AUDIT HIPAA_Audit
    TO FILE ( FILEPATH ='\\SQLPROD_1\Audit\' );

B. Creating a server audit with a Windows Application log target with options

The following example creates a server audit called HIPPA_Audit with the target set for the Windows Application log. The queue is written every second and shuts down the SQL Server engine on failure.

CREATE SERVER AUDIT HIPAA_Audit
    TO APPLICATION_LOG
    WITH ( QUEUE_DELAY = 1000,  ON_FAILURE = SHUTDOWN);

C. Creating a server audit containing a WHERE clause

The following example creates a database, schema, and two tables for the example. The table named DataSchema.SensitiveData will contain confidential data and access to the table must be recorded in the audit. The table named DataSchema.GeneralData does not contain confidential data. The database audit specification audits access to all objects in the DataSchema schema. The server audit is created with a WHERE clause that limits the server audit to only the SensitiveData table. The server audit presumes a audit folder exists at C:\SQLAudit.

CREATE DATABASE TestDB;
GO
USE TestDB;
GO
CREATE SCHEMA DataSchema;
GO
CREATE TABLE DataSchema.GeneralData (ID int PRIMARY KEY, DataField varchar(50) NOT NULL);
GO
CREATE TABLE DataSchema.SensitiveData (ID int PRIMARY KEY, DataField varchar(50) NOT NULL);
GO
-- Create the server audit in the master database
USE master;
GO
CREATE SERVER AUDIT AuditDataAccess
    TO FILE ( FILEPATH ='C:\SQLAudit\' )
    WHERE object_name = 'SensitiveData' ;
GO
ALTER SERVER AUDIT AuditDataAccess WITH (STATE = ON);
GO
-- Create the database audit specification in the TestDB database
USE TestDB;
GO
CREATE DATABASE AUDIT SPECIFICATION [FilterForSensitiveData]
FOR SERVER AUDIT [AuditDataAccess] 
ADD (SELECT ON SCHEMA::[DataSchema] BY [public])
WITH (STATE = ON);
GO
-- Trigger the audit event by selecting from tables
SELECT ID, DataField FROM DataSchema.GeneralData;
SELECT ID, DataField FROM DataSchema.SensitiveData;
GO
-- Check the audit for the filtered content
SELECT * FROM fn_get_audit_file('C:\SQLAudit\AuditDataAccess_*.sqlaudit',default,default);
GO

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