What Are Disk Quotas?

Updated: March 28, 2003

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

In this section

Disk quotas track and control disk space usage for NTFS volumes, allowing administrators to control the amount of data that each user can store on a specific NTFS volume. By using disk quotas, you can configure Microsoft Windows Server 2003 to do the following:

  • Log an event when a user exceeds a specified disk space warning level. The warning level specifies the point at which a user is nearing the quota limit.

  • Prevent further use of disk space or log an event when a user exceeds a specified disk space limit.

If users are sharing file disk space on a server, they can consume considerable disk space when saving documents, graphics, and other files. This can be problematic if some users need to use more disk space than other users, resulting in some users not having enough disk space to store their files on the volume.

An administrator can solve this problem by enacting a Group Policy or a computer policy that limits the amount of disk space each user has on the volume. The administrator can also adjust quotas to the user’s needs because user’s are tracked on a per-user basis, per-volume.

Common Core Scenarios for Using Disk Quotas

Disk quotas can be used in several ways, depending on the needs and resources of your organization.

Limited number of servers

When you have a limited number of file servers and applications installed on those servers, you can use disk quotas to track disk usage. If you have a large number of users accessing a small group of file servers, you can set disk quotas to allocate the amount of space each user is allowed on a particular server. The disk quotas apply to all users whether they are local or remote users of the server.

Limited space on a server volume

When you have limited space on a server volume with multiple local and remote users accessing applications on that volume, you can set a specific amount of hard disk space for each user by enabling disk quotas.

Monitoring but not limiting disk space usage

If you have plenty of disk space on a volume, as well as enough servers in your organization, you might not want to enforce disk quotas. However, by enabling disk quotas, you can monitor the disk space usage of each user without restricting any user from accessing additional space when a limit is reached. You can then adjust the quota according to the demands of the job. Later, you can increase or decrease allocated space as necessary.

Dependencies on Other Technologies

Disk quotas rely on the following technologies:


The server volume must be formatted as NTFS. Disk quotas do not work on FAT volumes.

Active Directory

The Active Directory directory Service is required if you want to set a Group Policy for a computer or for a group of users. You must be the system administrator in the domain in which the server resides. Disk Quotas obtains a list of the user account names from the domain controller or from Local Users and Groups in the Computer Management console.

Group Policy

Using Group Policy you can create and apply a disk quota policy setting to a set of targeted users and computers in an Active Directory environment.

The following figure, “Relationship of Disk Quotas to Other Windows Server 2003 Technologies,” shows the relationship of disk quotas to other technologies in Windows Server 2003.

Relationship of Disk Quotas to Other Windows Server 2003 Technologies

Disk Quota Physical Structure

In the preceding diagram, “Relationship of Disk Quotas to Other Windows Server 2003 Technologies,” an administrator accesses an NTFS volume on a server running Windows Server 2003 to set disk quotas. When the administrator uses Disk Management to set disk quotas, Active Directory returns a list of users in the domain. Based on the names in the list, the administrator can create a disk quota Group Policy or computer policy for each user on that particular NTFS volume, regardless of where the user is located.

Related Information

The following resources contain additional information that is relevant to this section.

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