IT administrators have been working with and around Active Directory since the introduction of the technology in Windows 2000 Server. Windows 2000 Server was released on February 17, 2000 but many administrators began working with Active Directory in late 1999 when it was released to manufacturing (RTM) on December 15, 1999.
This part of the tutorial tells you about SYSOL.
What is SYSVOL?
The system volume (SYSVOL) is a special directory on each DC. It is made up of several folders with one being shared and referred to as the SYSVOL share.
The default location is %SYSTEMROOT%SYSVOLsysvol for the shared folder, although you can change that during the DC promotion process or anytime thereafter. SYSVOL is made up of Folders. The folders are used to store:
- Group Policy templates (GPTs), which are replicated via SYSVOL replication. The Group Policy container (GPC) is replicated via Active Directory replication.
- Scripts, such as startup scripts that are referenced in a GPO.
- Junction points. Junction points work like a shortcut. One directory can point to a different directory. In File Explorer, a junction point and a directory look and feel the same. You can view junction points by running the dir /AL /S command.
SYSVOL Replication Occurs over DFSR
Initially with Windows 2000 Server, Windows Server 2003, and Windows Server 2003 R2, replication was handled by File Replication Service (FRS). Starting with domains created in Windows Server 2008, DFSR is the default SYSVOL replication method. FRS wasn’t very efficient. Any time that a file in SYSVOL changed, FRS replicated the entire file to all domain controllers.
With DFSR, only the changed part of the file is replicated, although only for files over 64KB.
DFSR Uses Remote Differential Compression (RDC)
RDC is what enables the replication of only changed data. Some admins may remember migrating from FRS to DFSR when Windows Server 2008 was released.
Without reliable and timely replication, one side effect that users may experience is inconsistent GPO application since the SYSVOL data may not be in sync across all of the DCs.
More information about Active Directory basisc you will find in our AD tutorial for begginners.
Expert in Microsoft infrastructure and cloud-based solutions built around Windows, Active Directory, Azure, Microsoft Exchange, System Center, virtualization, and MDOP. In addition to authoring books, Brian writes training content, white papers, and is a technical reviewer on a large number of books and publications.
