How Does NT 5.0's Quota Management System Measure Up?

Microsoft has never included a quota management system in Windows NT--until now. NT Server 5.0 and NT Workstation 5.0 will be shipping with an integrated quota management system. Because Microsoft is including this system within the core NT operating system (OS), NT Server and NT Workstation customers can benefit from quota management features without purchasing additional software.

However, some industry experts say that NT 5.0's quota management system is too little, too late. Because the quota management system lacks directory-based quotas and is based on rigid partitioning, these experts believe it is inferior to other quota management solutions.

You need to decide for yourself about NT 5.0's quota management system. By reading the following information about how the quota management system works (be sure to read the sidebar "Frequently Asked Questions About Quotas," page 174) and by weighing the system's pros and cons, you can make an informed decision.

The Basics of the Quota Management System
Organizations of all sizes can take advantage of NT 5.0's quota management system. Large enterprises can use quotas to limit usage on workstation machines with multiple users. Small departments can limit permissions to a disk and then quota that disk for added protection against users consuming all disk space. The quota management system is flexible because it monitors and limits disk-space usage on a per user, per volume basis.

Per user. Ownership is the key to disk usage in NT 5.0. NT enforces per user quotas on only those files that users own. For example, if Bill modifies Jane's report without taking ownership of it, NT will apply that report's disk-space usage against Jane's quota. But if Bill takes ownership of the file, NT will reduce Jane's disk-space usage by the file's amount and increase Bill's disk-space usage by the same value.

Is Microsoft's introduction of quota management too little, too late? I don't think so. What's your verdict?
NT uses two values­quota limit and quota warning threshold­to monitor and limit disk-space usage. The quota limit is the fixed amount of disk space available to a user. The quota warning threshold specifies the amount of disk space available before NT generates an alert; usage above this threshold automatically adds warning events to NT's event logs.

Per volume. The quota management system works on NTFS volumes only. (You cannot use quotas with FAT drives.) In addition, because Microsoft revamped NTFS under NT 5.0, you can use the quota management system only on NTFS 5.0 volumes.

Each NTFS volume has a separate set of quotas, even if two volumes are on the same physical disk. Thus, you can better customize quotas to meet the needs of groups of users. For example, you can set the default quota to 20MB for all users on drive E and to 50MB for all users on drive F. However, having separate volume quotas means that if you have 12 NTFS volumes that need quotas, you will have to set and monitor the quotas on each volume separately. Fortunately, you can easily set up and monitor quotas.

Setting Up Disk Quotas
Suppose you want to use NT 5.0 beta 1's quota management system on an NTFS 5.0 volume on drive C. To set quotas, you must have administrator privileges on the local computer that holds the volume. If you do, here's how you set up a quota.

Under NT's Start menu, open Explorer, right-click drive C, select Properties, and click the Quota tab. A message will appear stating that you must upgrade to NTFS 5.0 to enable disk quotas. At first, this message might seem odd. Microsoft released NTFS 5.0 expressly for use in NT 5.0, so why doesn't NT 5.0 have NTFS 5.0 installed? Microsoft had a good reason to use NTFS 4.0 rather than NTFS 5.0 as the default format for a disk partition: to ensure volume compatibility with previous NT versions. In other words, an NTFS 5.0 volume cannot be read by an NT 4.0 (or earlier) server. So, if you want to use a previous NT version on your disk, do not upgrade to NTFS 5.0. However, if you don't upgrade to NTFS 5.0, you can't use quotas on that volume. (Microsoft is simplifying the NTFS 5.0 upgrade process, so the default for volumes in a future beta release of NT 5.0 might be NTFS 5.0.)

If you decide to upgrade to NTFS 5.0, you go to a command-prompt window and type


After you reboot, the NTFS 5.0 upgrade will automatically occur.

Once the upgrade is complete, go to the Quota tab in Properties again. Instead of getting the upgrade message, you will now see status information and several quota options, as Screen 1 shows. The first time this screen appears, the stoplight icon will be red and the Status message will read Disk quotas are disabled. In addition, the Enable quota management check box will not be selected and the other fields will be unavailable. In Screen 1, however, I have selected the Enable quota management check box so that you can better see those fields.

After selecting the Enable quota management check box, you must specify whether NT should deny disk space to users who have exceeded their quota limit. This decision can be difficult. For example, suppose Barry is setting quota limits for his company's graphics department, which has been allocated a 9GB volume on a server. Ordinarily, Barry would limit users to 50MB, but users in this department sometimes need extra disk space for a brief period to process large graphics files. If he denies these users extra disk space, they will be forced to reduce their disk usage below their quota limit before they can save any more data. If he lets the users go past their limit, they can use the disk as a temporary storage area (provided enough disk space is available) to process large graphics files. Barry decides not to deny these users extra disk space, but tells them to take the quota warnings seriously so that the disk doesn't become full.

Barry decides to regularly monitor disk usage for this department to make sure problems don't arise. At first, the users heeded the quota warnings and reduced their disk usage after they finished with a large project. But then an unwritten but well-known law­the law that says data expands to fill the disk space available­holds true. The users start ignoring the warnings, and the disk regularly borders on being full. Barry now has an even tougher decision: start denying these users extra disk space (an action with which they will likely be upset) or exceed his budget to purchase additional disk space.

Based on Barry's experience, you decide to deny disk space to users exceeding their quota limit. Now you must set the options on usage limits for new users. You can choose to not limit disk usage, or you can limit disk space, specifying the limit in terms of KBs, MBs, or GBs. Wanting to limit disk space for new users, you set the quota limit at 50MB, with the warning threshold at 40MB.

You're satisfied with the choices you made on the Quota tab, so you click Apply. A warning message appears stating that you should enable the quota system only if you intend to use quotas on the disk volume. You click OK, and the Quota tab's stoplight icon goes to amber. The accompanying Status message reads Rebuilding disk quota information. When NT finishes this task, you get a green light and the Status message Disk quota system is active, as Screen 2 shows.

Viewing Quotas and Disk Usage
With quotas enabled on the volume, you'll want to see users' quota limits and disk-space usage. Clicking Quota Entries on the Quota tab will take you to a dialog box with this information. As Screen 3, page 176, shows, the first time you open the Quota Entries dialog box, NT informs you that it is retrieving the usernames. Because NT uses security IDs (SIDs) to apply quotas to users, NT must contact a domain controller to retrieve the names that correspond to the SIDs. When all the SIDs have matching names, you'll see a dialog box like Screen 4. NT saves the usernames, so it doesn't have to repeat this slow retrieval process each time you open Quota Entries.

Quota Entries contains much data. Here are five tips on how to better navigate through that information.

  1. When looking at the Quota Entries dialog box, you'll notice a group, Administrators, that has no quota limits set. NT automatically adds this group and gives it unlimited disk space. Do not change this default, because the group--not a user in the group--owns all the files that the administrators create. For example, if Dawn is an administrator and she creates a file while serving in that capacity, the Administrators group, not Dawn, owns that file. If you limit the Administrators group's disk-space usage, you might limit the administrators' ability to manage the NT system.
    1. A column that is useful but not automatically displayed is Network Domain. As Screen 4 shows, this far-left column lists the network domains in which users reside. You can use the View drop-down menu to add this column to the dialog box.
    2. When looking at rows of numbers, you can't always discern the highest or lowest users of disk space. Fortunately, you can click the Amount Used and Percent Used column headings to instantly rank the data from highest to lowest disk-space user.
    3. If you want to find the quota limit or disk-space usage of a particular user, you can use the Search function. You can type a username into the blank text box and press Enter, or you can click Search (represented by the magnifying glass) and type the username into the text box that appears. The Search function is particularly useful when you have thousands of user entries.
    4. You can use the Properties function to change a user's quota. To view a user's properties, highlight the username and click Properties (represented by a hand pointing to writing on a piece of paper). As Screen 5 shows, you can also see the disk space remaining for that user.

    You can modify several user entries at once by highlighting the usernames you want and clicking Properties. If you use the search function to find the usernames, each new highlighted result adds to your previous result instead of replacing it. In other words, if you want to view the properties of 12 users, you can search for each one and then click Properties after you've highlighted all 12. Alternatively, you can use the Ctrl and Shift keys to individually select the users (just as you do in NT Explorer) or you can type the name of each user, then click Properties. To start a new group of users, you click an unhighlighted user; the previous 12 users will become unhighlighted, and the user you clicked will become highlighted.

    Alerting Administrators and Users of Problems
    Whenever a user's disk space exceeds the quota threshold, NT writes an event to the System Log on the computer that holds the particular volume. NT logs a similar event when a user goes over the quota limit. You can use the Event Viewer to review the System Log for these events. The Event Viewer is the new name for the Event Log. As Screen 1 and Screen 2 show, the button that brings up the Event Viewer still reads Event Log.

    The Quota Entries dialog box will warn you when users are going over the warning threshold and quota limit. As Screen 6 shows, when users go over the warning threshold, the Status column displays the yellow Warning icon. When users go over the quota limit, the Status column displays the red Above Limit icon.

    If you opted to deny users extra disk space when they exceed the quota limit, they'll receive an Insufficient disk space error message when they try to use more disk space. If users question this message and perform a free-space check, such as typing DIR from a command prompt, NT will display only the free space available to them (i.e., their quota limit minus the space used by their existing files).

    Using the Quota Management System Efficiently
    NT 5.0 includes several functions that help you use the quota management system more efficiently. Two such functions are Import and Export. These functions, which are in the Quota Entries dialog box, can help you transfer a user's records if they need to be on different volumes.

    Here's how the Import and Export functions work. After you select the user's records you want to export, choose Export from the File menu and save the results in a destination folder of your choice. Open the Quota Entries dialog box of the volume that is to receive these records. Select Import from the File menu, and specify the previously saved file. If no quota entry exists for that user, NT will create one. If a quota entry exists, NT will update that existing entry with the new threshold and limit settings.

    An even easier way to transfer a user's records is to open the Quota Entry dialog boxes for both your source and destination volumes. Then drag the records from the source volume and drop them into the destination volume. You can even drag records to documents that support the ASCII, Unicode, Rich Text Format (RTF), or Comma Separated Value (CSV) formats. You simply open the Quota Entry dialog box and a document in an application that supports these formats, such as Word and Excel. After you select the quota entries you want in your report, drag the information to your document. The data will retain the same formatting it had in the Quota Entry dialog box.

    Another quota management option that can help you is the ability to manage quotas on remote machines. You can perform the same quota management tasks on a remote volume as you can perform on a local volume, provided you meet three requirements. First, the remote machine's target drive must be NTFS 5.0. Second, you must have Administrator privileges on the computer in which the remote volume resides. Third, you must map a network drive to the remote volume.

    What's Your Verdict?
    Is Microsoft's introduction of quota management in NT 5.0 too little, too late? I don't think so. Microsoft has successfully included a reasonable number of disk-quota management features in the core product. With NT 5.0's quota management feature, you can set quotas in any environment. Larger organizations might still want to purchase a third-party quota management utility, but at least they have the luxury of choosing to do so.

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