Disk quotas overview

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

Disk quotas overview

Disk quotas track and control disk space usage for NTFS volumes. Administrators can configure Windows to:

  • Prevent further disk space use and log an event when a user exceeds a specified disk space limit, that is, the amount of disk space a user is allowed to use.

  • Log an event when a user exceeds a specified disk space warning level, that is, the point at which a user is nearing his or her quota limit.

When you enable disk quotas, you can set two values: the disk quota limit and the disk quota warning level. For example, you can set a user's disk quota limit to 500 megabytes (MB), and the disk quota warning level to 450 MB. In this case, the user can store no more than 500 MB of files on the volume. If the user stores more than 450 MB of files on the volume, you can configure the disk quota system to log a system event. You must be a member of the Administrators group to administer quotas on a volume. For instructions on setting disk quota values, see Assign default quota values.

You can specify that users can exceed their quota limit. Enabling quotas and not limiting disk space use are useful when you do not want to deny users access to a volume but want to track disk space use on a per-user basis. You can also specify whether or not to log an event when users exceed either their quota limit or their quota warning level.

When you enable disk quotas for a volume, volume usage is automatically tracked for all users from that point on.

You can enable quotas on local volumes, network volumes, and removable drives as long as they are formatted with the NTFS file system. In addition, network volumes must be shared from the volume's root directory and removable drives must be shared. Volumes formatted with the version of NTFS used in Windows NT 4.0 are upgraded automatically by Windows Setup.

You cannot use file compression to prevent users from exceeding their quota limits because compressed files are tracked based on their uncompressed size. For example, if you have a 50 MB file that is 40 MB after it is compressed, Windows counts the file's original 50 MB size toward the quota limit.