Managing Disk Quotas

Article
03/24/2009

Windows 2000 disk quotas track and control disk storage usage on a per-user, per-volume basis. Windows 2000 tracks disk quotas for each volume, even if the volumes are on the same hard disk. Because quotas are tracked on a per-user basis, every user's disk space is tracked regardless of the folders in which the user stores files.

About Windows 2000 Disk Quotas

The following list describes several important characteristics of Windows 2000 disk quotas.

Windows 2000 calculates disk space usage for users based on the files and folders they own. When a user copies or saves a file to an NTFS volume or takes ownership of a file on an NTFS volume, Windows 2000 charges the disk space for the file against the user's quota limit.
Windows 2000 ignores compression when it calculates hard disk space usage. Users are charged for each uncompressed byte, regardless of how much hard disk space is actually used. In part, this charge is made because file compression produces different degrees of compression for different types of files. Different file types that are the same size when compressed might end up to be very different sizes when they are compressed.
When disk quotas are enabled, the free disk space Windows 2000 reports to applications for the volume is the amount of space remaining within the user's disk quota limit. For example, a user whose files occupy 50 megabytes (MB) of an assigned disk quota limit of 100MB will show 50 MB of free space even if the volume contains several gigabytes of free space.

Disk quotas can be used to monitor and control hard disk space usage. System administrators can perform the following tasks:

Set a disk quota limit to specify the amount of disk space for each user.
Set a disk quota warning to specify when Windows 2000 should log an event, indicating that the user is nearing his or her limit.
Enforce disk quota limits and either deny users access if they exceed their limit or allow them to continue access.
Log an event when a user exceeds a specific disk space threshold. For example, a threshold might be when users exceed their quota limit or when they exceed their warning level.

After enabling disk quotas for a volume, Windows 2000 collects disk usage data for all users who own files and folders on the volume. This allows monitoring of volume usage on a per-user basis. By default, only members of the Administrators group can view and change the quota settings. However, the administrator can allow users to view quota settings.

Setting disk quotas

Authorized administrators can enable disk quotas and enforce disk quota warnings and limits for all users or for individual users. To enable disk quotas:

Double-click My Computer to open it.
Right-click the disk volume for which disk quotas is to be enabled, and then click Properties. If the volumes are not formatted with the NTFS file system, or if the user is not a member of the Administrators group, the Quota tab is not displayed in the volume's Properties dialog box.
In the Properties dialog box, click the Quota tab.
On the Quota properties page, click the Enable quota management check box, configure the disk quota options, and then click OK. The options on the Quota tab are described in the following table.

Option	Description
Enable Quota Management	Select this box to enable disk quota management.
Deny Disk Space To Users Exceeding Quota Limit	Select this box so that when users exceed their hard disk space allocation, they receive an "out of disk space" message and cannot write to the volume.
Do Not Limit Disk Usage	Click this option when it is not necessary to limit the amount of hard disk space for users.
Limit Disk Space To	Configure the amount of disk space that users can use.
Set Warning Level To	Configure the amount of disk space that a user can fill before Windows 2000 logs an event, indicating that a user is nearing his or her limit.
Quota Entries	Click this button to open the Quota Entries for a dialog box, where authorized administrators can add a new entry, delete an entry, and view the per-user quota information.

To enforce identical quota limits for all users, enter the appropriate values in the Limit Disk Space To text box and the Set Warning Level To text box, and then select the Deny Disk Space To Users Exceeding Quota Limit check box.

Windows 2000 monitors usage and will not allow users to create files or folders on the volume when they reach the limit.

Determining the status of disk quotas

Authorized administrators can determine the status of disk quotas in the Properties dialog box for a disk by checking the traffic light icon and reading the status message to its right. The traffic light colors and the status they indicate are as follows:

A red traffic light indicates that disk quotas are disabled.
A yellow traffic light indicates that Windows 2000 is rebuilding disk quota information.
A green traffic light indicates that the disk quota system is active.

Monitor disk quotas

Authorized administrators can use the Quota Entries For <volume_name> dialog box to monitor usage for all users who have copied, saved, or taken ownership of files and folders on the volume. Windows 2000 scans the volume and monitors the amount of disk space in use by each user. The Quota Entries For <volume_name> dialog box allows authorized administrators to view the following information:

The amount of hard disk space that each user uses.
Users who are over their quota-warning threshold, which is signified by a yellow triangle.
Users who are over their quota limit, which is signified by a red circle.
The warning threshold and the disk quota limit for each user.

Volume usage is tracked for all users owning files on a volume where the disk quota system is active. Existing users owning files are limited to the default disk quota unless authorized administrators modify the user quota setting using the Quota Entries For <volume_name> dialog box. User not owning files on the volume will not appear in the Quota Entries For <volume_name> dialog box but can also be added manually. By default, quota limits are not applied to the Administrators local group.

Exceeding disk quota limits

When the Deny disk space to users exceeding quota limit option is selected, users who exceed their quota limit receive an "insufficient disk space" error from Windows and cannot write additional data to the volume without first deleting or moving some existing files from it.

Individual programs determine their own error handling for this condition. To the program, it appears that the volume is full. If this option is left cleared, users can exceed their quota limit. Enabling quotas and not limiting disk space use are useful when administrators do not want to deny users access to a volume, but want to track disk space use on a per-user basis. Authorized administrators can also specify whether or not to log an event when users exceed either their quota warning level or their quota limit.

When the Log event when a user exceeds their quota limit option is selected, an event is written to the Windows system log on the computer running disk quotas whenever users exceed their quota limit. Authorized administrators can view these events with Event Viewer, filtering for disk event types.

When the Log event when a user exceeds their warning level option is selected, an event is written to the Windows system log on the computer running disk quotas whenever users exceed their quota warning level. Authorized administrators can view these events with Event Viewer, filtering for disk event types. Unless a trigger is set to do so, users are not warned of this event.

To modify user disk space and warning levels:

Right-click the volume for which quota values are to be modified, and then click Properties.
In the Properties dialog box, click the Quota tab.
On the Quota properties page, click Quota Entries.
In the Quota Entries window, click the entries for the users whose options are to be modified, and on the Quota menu, click Properties.
In the Quota Settings dialog box, modify any of the following options that are to be changed, and then click OK:

Do not limit disk usage. Click to track disk space usage without limiting disk space.

Limit disk space to. Activates fields for limiting disk space and setting warning levels. Type a numeric value in the text field, and select a disk space limit unit from the drop-down list. Authorized administrators can use decimal values (for example, 20.5 MB). The value entered cannot exceed the maximum capacity of the volume.

To delete quota entries:

Right-click the volume for which quota entries are to be deleted, and then click Properties.
In the Properties dialog box, click the Quota tab.
On the Quota properties page, click Quota Entries.
In the Quota Entries window, click the entries for the users to be deleted, and then from the Quota menu, click Delete quota entry.
If the Disk Quota dialog box appears, click Yes, click the files to take action on, click one of the following buttons, and then click Close.

Delete. Deletes selected files from the volume.

Take ownership. Gives ownership of selected files on the volume.

Move. Moves selected files to a specified volume.

To disable disk quotas:

Right-click the disk volume for which disk quotas are to be disabled, and then click Properties.
In the Properties dialog box, click the Quota tab.
On the Quota tab, clear the Enable quota management check box, and then click OK.