In Operations Manager 2007, Audit Collection Services (ACS) provides a means to collect records generated by an audit policy and store them in a centralized database. By default, when an audit policy is implemented on a Microsoft Windows computer, that computer automatically saves all events generated by the audit policy to its local Security log. This is true for Windows workstations as well as servers. In organizations that have strict security requirements, audit policies can quickly generate large volumes of events.

Using ACS, organizations can consolidate individual Security logs into a centrally managed database and can filter and analyze events using the data analysis and reporting tools provided by Microsoft SQL Server. With ACS, only a user who has specifically been given the right to access the ACS database can run queries and create reports on the collected data.

In Operations Manager 2007, the deployment of ACS involves the following components:

ACS Forwarders

The service that runs on ACS forwarders is included in the Operations Manager agent. By default, this service is installed but not enabled when the Operations Manager agent is installed. You can enable this service for multiple agent computers at once using the Enable Audit Collection task. After you enable this service, all security events are sent to the ACS collector in addition to the local Security log.

ACS Collector

The ACS collector receives and processes events from ACS forwarders and then sends this data to the ACS database. This processing includes disassembling the data so that it can be spread across several tables within the ACS database, minimizing data redundancy, and applying filters so that unnecessary events are not added to the ACS database.

The number of ACS forwarders that can be supported by a single ACS collector and ACS database can vary, depending on the number of events that your audit policy generates, the role of the computers that the ACS forwarders monitor (such as domain controller versus member server), the level of activities on the computer, and the hardware on which the ACS collector and ACS database run. If your environment contains too many ACS forwarders for a single ACS collector, you can install more than one ACS collector. Each ACS collector must have its own ACS database.

An ACS Collector must be installed on computers running Windows Server 2003 and later,and must have a minimum of 1 gigabyte (GB) of RAM, with 2 GB recommended. Also, it must have at least a 1.8 gigahertz (GHz) processor, with a 2.8 GHz processor recommended and 10 GB of hard disk space available, at a minimum, with 50 GB recommended. The computer you select as an ACS collector must be an Operations Manager 2007 management server and for security reasons, it must also be a member of an Active Directory domain.

On each computer on which you plan to install the ACS collector, you must download and install the latest version of the Microsoft Data Access Components (MDAC) from the Microsoft Web site. To learn more about MDAC, see "Learning Microsoft Data Access Components (MDAC)" at

ACS Database

The ACS database is the central repository for events that are generated by an audit policy within an ACS deployment. The ACS database can be located on the same computer as the ACS collector, but for best performance, each should be installed on a dedicated server.

The server that hosts the ACS database must have Microsoft SQL Server 2005 or SQL Server 2008. You can choose an existing or new installation of SQL Server. The Enterprise edition of SQL Server is recommended because of the stress of daily ACS database maintenance.

If you use SQL Server standard edition, the database must pause during daily maintenance operations. This may cause the ACS collector queue to fill with requests from ACS forwarders. A full ACS collector queue then causes ACS forwarders to be disconnected from the ACS collector. Disconnected ACS forwarders reconnect after the database maintenance is complete and the queue backlog is then processed. To ensure no audit events are lost allocate a sufficient amount of hard disk space for the local security log on all ACS forwarder.

SQL Server enterprise edition can continue to service ACS forwarder requests, although at a lower performance level, during daily maintenance operations. For more information on the ACS collector queue and ACS forwarder disconnection see ACS Capacity Planning and Monitoring ACS Performance.

The ACS database should run on a computer that has a minimum of 1 GB of RAM, with 2 GB recommended. Also, it must have at least a 1.8 GHz processor, with a 2.8 GHz processor recommended and 20 GB of hard disk space available, at a minimum, with 100 GB recommended. If your SQL Server has more than 2 GB of memory some additional configuration steps are needed. For more information and the steps needed, see "How to configure SQL Server to use more than 2 GB of physical memory" at

See Also

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