When you install Active Directory Domain Services (AD DS), you specify where the Active Directory database, log files, and the SYSVOL shared folder will be placed on the server. The database stores information about the users, computers, and other objects on the network. The log files record activities that are related to AD DS, such as information about an object being updated. SYSVOL stores Group Policy objects and scripts. By default, SYSVOL is part of the operating system files in the %windir% directory.
Consider the following factors when you decide where to place AD DS files:
Backup and recovery considerations for placing AD DS files
For a simple installation in which the server has only one hard disk, you can simply accept the default installation settings that are supplied by the Active Directory Domain Services Installation Wizard. However, you must create at least two volumes on that one hard disk. One volume is required for critical-volume data and another volume is required for backup.
When you use Windows Server Backup or the Wbadmin.exe command-line tool to back up a domain controller, you must back up at least the system state data so that you can use the backup to recover the server. The volume that you use to store the backups cannot be the same volume that hosts system state data. This requirement can affect where you decide to place AD DS files. The system components that make up system state data depend on the server roles that are installed on the computer. The system state data includes at least the following data, plus additional data, depending on the server roles that are installed:
- Registry
- COM+ Class Registration database
- Boot files
- Active Directory Certificate Services
(AD CS) database
- Volume that hosts the Active Directory
database (Ntds.dit)
- Volume that hosts the Active Directory
database log files
- SYSVOL directory
- Cluster service information
- Microsoft Internet Information Services (IIS)
metadirectory
- System files that are under Windows Resource
Protection
For example, if you are installing AD DS on a server that has one hard disk, you might create the following logical volumes to accommodate backups:
- Drive C, which hosts all the critical volume
data
- Drive D, which is used as a target for
Windows Server Backup or Wbadmin.exe
For more information about backing up and recovering a domain controller, see the Step-by-Step Guide for Active Directory Domain Services Backup and Recovery (http://go.microsoft.com/fwlink/?LinkId=93077).
Performance considerations for placing AD DS files
For more complex installations, you may configure your hard disk storage to optimize the performance of AD DS. Because the database and log files utilize disk storage space in different ways, you can improve AD DS performance by devoting separate hard disk spindles for each.
For example, suppose that a server has four available hard disk drives that are labeled as follows:
- Drive C, which includes the operating system
files
- Drive D, which is not used
- Drive E, which is not used
- Drive F, which is used for backup
On this server, you can improve AD DS performance the most by installing the database and log files on separate drives that are devoted to those resources, such as drives D and E. This can help improve the performance of searches against the database because one disk spindle can be devoted solely to that activity. If a large number of changes are ever made at one time, this configuration also reduces the chance of bottlenecks developing on the disk that hosts the log files. You can place SYSVOL on drive C with the operating system files.