| title | Server Configuration: c2 audit mode | |||||
|---|---|---|---|---|---|---|
| description | Get acquainted with C2 audit mode, a SQL Server configuration option that can help you profile system activity and track possible security policy violations. | |||||
| author | rwestMSFT | |||||
| ms.author | randolphwest | |||||
| ms.date | 08/26/2025 | |||||
| ms.service | sql | |||||
| ms.subservice | configuration | |||||
| ms.topic | how-to | |||||
| helpviewer_keywords |
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[!INCLUDE SQL Server]
C2 audit mode can be configured through [!INCLUDE ssManStudioFull] or with the c2 audit mode option in sp_configure. Selecting this option configures the server to record both failed and successful attempts to access statements and objects. This information can help you profile system activity and track possible security policy violations.
Note
[!INCLUDE ssNoteDepFutureAvoid] The C2 security standard has been superseded by Common Criteria Certification. See the common criteria compliance enabled Server Configuration Option.
C2 audit mode data is saved in a file in the default data directory of the instance. If the audit log file reaches its size limit of 200 megabytes (MB), [!INCLUDE ssNoVersion] creates a new file, close the old file, and write all new audit records to the new file. This process continues until the audit data directory fills up or auditing is turned off. To determine the status of a C2 trace, query the sys.traces catalog view.
Important
C2 audit mode saves a large amount of event information to the log file, which can grow quickly. If the data directory in which logs are being saved runs out of space, [!INCLUDE ssNoVersion] shuts itself down. If auditing is set to start automatically, you must either restart the instance with the -f flag (which bypasses auditing), or free up additional disk space for the audit log.
Requires membership in the sysadmin fixed server role.
The following example turns on C2 audit mode.
EXECUTE sp_configure 'show advanced options', 1;
GO
RECONFIGURE;
GO
EXECUTE sp_configure 'c2 audit mode', 1;
GO
RECONFIGURE;
GO