Designing a Disk Quota Strategy

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

To prevent file servers from filling to capacity without warning, use disk quotas to track and control disk space usage on file servers. Windows Server 2003 provides disk quota functionality that tracks quotas on a per-user, per-volume basis. After you enable the warning level and limit, they apply to all users who own files stored on the volume. Any user who creates a new file is automatically assigned the current warning level and limit.

Windows Server 2003 quotas are well suited for volumes that store user data, such as redirected My Documents folders or other per-user folders. For example, an organization uses Group Policy to redirect its employees’ My Documents and My Pictures folders to a file server volume that stores only user data, not group data. After evaluating the storage needs of users in the organization, the administrator chooses to set storage limits by enforcing a 300-MB disk quota for each user. The administrator also sets a 270-MB warning level. If a user needs additional storage, the user must get approval from his or her manager before the administrator can increase the quota for the individual user.

Windows Server 2003 disk quotas are not designed for project-oriented scenarios in which a shared folder is given a quota that is shared among a specified set of users. A wide range of Windows Server 2003–compatible, third-party products provide group quotas, per-folder quotas, and threshold event features that this scenario requires.

To design a quota strategy for volumes that store user data, review the following topics. For an Excel spreadsheet to assist you in documenting your disk quota design decisions, see "Shadow Copy and Disk Quota Configuration Worksheet" (Sdcfsv_7.xls) on the Windows Server 2003 Deployment Kit companion CD (or see "DFS Configuration Worksheet" on the Web at https://www.microsoft.com/reskit).

File system requirements

Disk quotas are available only on NTFS volumes.

Tracking quotas vs. enforcing quotas

Tracking quotas is useful if you want to track use of disk space without denying users access to a volume. Enforcing quotas denies disk space to users who exceed their limit. Users can determine how much disk space they have available on the volume by viewing the properties of a mapped shared folder in Windows Explorer.

Determining how much disk space to provide to each user

You can change quotas on a per-user basis if some users require additional disk space. For example, the current limit might be 200 MB, but you can specify which users have a 500-MB limit. You cannot assign quotas on a per-group basis.

When setting quotas, make sure that you have enough disk space to accommodate existing users and that you have enough extra free space to accommodate future growth. Each file that is stored on the volume can use up to 64 KB of NTFS metadata that is not charged to a user’s quota. To avoid running out of disk space, you must leave sufficient disk space to accommodate this metadata.

Using disk quotas on server clusters

Use only domain-level accounts, because local accounts cannot be resolved when the disk fails over. For more information about configuring disk quotas on shared cluster disks, see article Q278365, "HOW TO: Configure Disk Quotas for a Shared Disk in a Cluster" in the Microsoft Knowledge Base. To find this article, see the Microsoft Knowledge Base link on the Web Resources page at https://www.microsoft.com/windows/reskits/webresources.

Logging quota events

Windows Server 2003 provides quota reporting by logging events in the event log when users exceed their warning level or quota limit. You can use Windows Management Instrumentation (WMI) for customized reporting by using the WMI classes Win32_DiskQuota, Win32_QuotaSetting, and Win32_VolumeQuotaSetting. For more information about WMI, see the Microsoft Windows Management Instrumentation (WMI) SDK link on the Web Resources page at https://www.microsoft.com/windows/reskits/webresources.

DFS provides a simple way to create custom quotas on different volumes that appear to users as different folders on the same volume. If you are using DFS to provide multiple link targets, note that each of these link targets can reside on a volume with different quota settings. To keep the user experience consistent, use the same quota settings for each volume.

Using disk quotas on shadow-copied volumes

You can enable shadow copies and disk quotas on the same volume, and shadow copies do not count against a user’s disk quota.

Note