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How Does NT 5.0's Quota Management System Measure Up?
For the first time, Microsoft will ship Windows NT 5.0 with quota management system. Learn how this new system monitors and limits disk-space usage.
Alistair G. Lowe-Norris
July 31, 1998
11 Min Read
Microsoft has never included a quota management system in WindowsNT--until now. NT Server 5.0 and NT Workstation 5.0 will be shipping with anintegrated quota management system. Because Microsoft is including this systemwithin the core NT operating system (OS), NT Server and NT Workstation customerscan benefit from quota management features without purchasing additionalsoftware.
However, some industry experts say that NT 5.0's quota management system is too little, too late. Because the quota management system lacksdirectory-based quotas and is based on rigid partitioning, these experts believeit is inferior to other quota management solutions.
You need to decide for yourself about NT 5.0's quota management system. Byreading 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 informeddecision.
The Basics of the Quota Management System
Organizations of all sizes can take advantage of NT 5.0's quota managementsystem. Large enterprises can use quotas to limit usage on workstation machineswith multiple users. Small departments can limit permissions to a disk and thenquota that disk for added protection against users consuming all disk space. Thequota management system is flexible because it monitors and limits disk-spaceusage on a per user, per volume basis.
Per user. Ownership is the key to disk usage in NT 5.0. NTenforces per user quotas on only those files that users own. For example, ifBill modifies Jane's report without taking ownership of it, NT will apply thatreport's disk-space usage against Jane's quota. But if Bill takes ownership ofthe file, NT will reduce Jane's disk-space usage by the file's amount andincrease 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 thresholdtomonitor and limit disk-space usage. The quota limit is the fixed amount of diskspace available to a user. The quota warning threshold specifies the amount ofdisk space available before NT generates an alert; usage above this thresholdautomatically adds warning events to NT's event logs.
Per volume. The quota management system works on NTFSvolumes only. (You cannot use quotas with FAT drives.) In addition, becauseMicrosoft revamped NTFS under NT 5.0, you can use the quota management systemonly on NTFS 5.0 volumes.
Each NTFS volume has a separate set of quotas, even if two volumes are onthe same physical disk. Thus, you can better customize quotas to meet the needsof groups of users. For example, you can set the default quota to 20MB for allusers on drive E and to 50MB for all users on drive F. However, having separatevolume quotas means that if you have 12 NTFS volumes that need quotas, you willhave to set and monitor the quotas on each volume separately. Fortunately, youcan 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 NTFS5.0 volume on drive C. To set quotas, you must have administrator privileges onthe local computer that holds the volume. If you do, here's how you set up aquota.
Under NT's Start menu, open Explorer, right-click drive C, selectProperties, and click the Quota tab. A message will appear stating that you mustupgrade to NTFS 5.0 to enable disk quotas. At first, this message might seemodd. Microsoft released NTFS 5.0 expressly for use in NT 5.0, so why doesn't NT5.0 have NTFS 5.0 installed? Microsoft had a good reason to use NTFS 4.0 ratherthan NTFS 5.0 as the default format for a disk partition: to ensure volumecompatibility with previous NT versions. In other words, an NTFS 5.0 volumecannot be read by an NT 4.0 (or earlier) server. So, if you want to use aprevious NT version on your disk, do not upgrade to NTFS 5.0. However, if youdon't upgrade to NTFS 5.0, you can't use quotas on that volume. (Microsoft issimplifying the NTFS 5.0 upgrade process, so the default for volumes in a futurebeta 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 andtype
CHKNTFS /E C:
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 andseveral 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 quotasare disabled. In addition, the Enable quota management check boxwill not be selected and the other fields will be unavailable. In Screen 1,however, I have selected the Enable quota management check box so thatyou can better see those fields.
After selecting the Enable quota management check box, you must specifywhether NT should deny disk space to users who have exceeded their quota limit.This decision can be difficult. For example, suppose Barry is setting quotalimits for his company's graphics department, which has been allocated a 9GBvolume on a server. Ordinarily, Barry would limit users to 50MB, but users inthis department sometimes need extra disk space for a brief period to processlarge graphics files. If he denies these users extra disk space, they will beforced to reduce their disk usage below their quota limit before they can saveany more data. If he lets the users go past their limit, they can use the diskas a temporary storage area (provided enough disk space is available) to processlarge 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'tbecome full.
Barry decides to regularly monitor disk usage for this department to makesure problems don't arise. At first, the users heeded the quota warnings andreduced their disk usage after they finished with a large project. But then anunwritten but well-known lawthe law that says data expands to fill thedisk space availableholds true. The users start ignoring the warnings, andthe disk regularly borders on being full. Barry now has an even tougherdecision: start denying these users extra disk space (an action with which theywill likely be upset) or exceed his budget to purchase additional disk space.
Based on Barry's experience, you decide to deny disk space to usersexceeding their quota limit. Now you must set the options on usage limits fornew 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 spacefor new users, you set the quota limit at 50MB, with the warning threshold at40MB.
You're satisfied with the choices you made on the Quota tab, so you clickApply. A warning message appears stating that you should enable the quota systemonly if you intend to use quotas on the disk volume. You click OK, and the Quotatab's stoplight icon goes to amber. The accompanying Status message reads Rebuildingdisk quota information. When NT finishes this task, you get a green lightand 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 limitsand disk-space usage. Clicking Quota Entries on the Quota tab will take you to adialog box with this information. As Screen 3, page 176, shows, the first timeyou open the Quota Entries dialog box, NT informs you that it is retrieving theusernames. Because NT uses security IDs (SIDs) to apply quotas to users, NT mustcontact 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. NTsaves the usernames, so it doesn't have to repeat this slow retrieval processeach time you open Quota Entries.
Quota Entries contains much data. Here are five tips on how to betternavigate through that information.
When looking at the Quota Entries dialog box, you'll notice a group,Administrators, that has no quota limits set. NT automatically adds this groupand gives it unlimited disk space. Do not change this default, because thegroup--not a user in the group--owns all the files that the administratorscreate. For example, if Dawn is an administrator and she creates a file whileserving in that capacity, the Administrators group, not Dawn, owns that file. Ifyou limit the Administrators group's disk-space usage, you might limit theadministrators' ability to manage the NT system.
A column that is useful but not automatically displayed is NetworkDomain. As Screen 4 shows, this far-left column lists the network domains inwhich users reside. You can use the View drop-down menu to add this column tothe dialog box.
When looking at rows of numbers, you can't always discern the highest orlowest users of disk space. Fortunately, you can click the Amount Used andPercent Used column headings to instantly rank the data from highest to lowestdisk-space user.
If you want to find the quota limit or disk-space usage of a particularuser, you can use the Search function. You can type a username into the blanktext box and press Enter, or you can click Search (represented by the magnifyingglass) and type the username into the text box that appears. The Search functionis particularly useful when you have thousands of user entries.
You can use the Properties function to change a user's quota. To view auser's properties, highlight the username and click Properties (represented by ahand pointing to writing on a piece of paper). As Screen 5 shows, you can alsosee the disk space remaining for that user.
You can modify several user entries at once by highlighting the usernamesyou want and clicking Properties. If you use the search function to find theusernames, each new highlighted result adds to your previous result instead ofreplacing 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 highlightedall 12. Alternatively, you can use the Ctrl and Shift keys to individuallyselect the users (just as you do in NT Explorer) or you can type the name ofeach user, then click Properties. To start a new group of users, you click anunhighlighted user; the previous 12 users will become unhighlighted, and theuser you clicked will become highlighted.
Alerting Administrators and Users of Problems
Whenever a user's disk space exceeds the quota threshold, NT writes an eventto the System Log on the computer that holds the particular volume. NT logs asimilar event when a user goes over the quota limit. You can use the EventViewer to review the System Log for these events. The Event Viewer is the newname for the Event Log. As Screen 1 and Screen 2 show, the button that brings upthe Event Viewer still reads Event Log.The Quota Entries dialog box will warn you when users are going over thewarning threshold and quota limit. As Screen 6 shows, when users go over thewarning threshold, the Status column displays the yellow Warning icon. Whenusers go over the quota limit, the Status column displays the red Above Limiticon.
If you opted to deny users extra disk space when they exceed the quotalimit, they'll receive an Insufficient disk space error message whenthey try to use more disk space. If users question this message and perform afree-space check, such as typing DIR from a command prompt, NT will display onlythe free space available to them (i.e., their quota limit minus the space usedby their existing files).
Using the Quota Management System Efficiently
NT 5.0 includes several functions that help you use the quota managementsystem more efficiently. Two such functions are Import and Export. Thesefunctions, which are in the Quota Entries dialog box, can help you transfer auser's records if they need to be on different volumes.Here's how the Import and Export functions work. After you select the user'srecords you want to export, choose Export from the File menu and save theresults in a destination folder of your choice. Open the Quota Entries dialogbox of the volume that is to receive these records. Select Import from the Filemenu, and specify the previously saved file. If no quota entry exists for thatuser, NT will create one. If a quota entry exists, NT will update that existingentry with the new threshold and limit settings.
An even easier way to transfer a user's records is to open the Quota Entrydialog boxes for both your source and destination volumes. Then drag the recordsfrom the source volume and drop them into the destination volume. You can evendrag records to documents that support the ASCII, Unicode, Rich Text Format(RTF), or Comma Separated Value (CSV) formats. You simply open the Quota Entrydialog box and a document in an application that supports these formats, such asWord and Excel. After you select the quota entries you want in your report, dragthe information to your document. The data will retain the same formatting ithad in the Quota Entry dialog box.
Another quota management option that can help you is the ability to managequotas on remote machines. You can perform the same quota management tasks on aremote volume as you can perform on a local volume, provided you meet threerequirements. First, the remote machine's target drive must be NTFS 5.0. Second,you must have Administrator privileges on the computer in which the remotevolume 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, toolate? I don't think so. Microsoft has successfully included a reasonable numberof disk-quota management features in the core product. With NT 5.0's quotamanagement feature, you can set quotas in any environment. Larger organizationsmight still want to purchase a third-party quota management utility, but atleast they have the luxury of choosing to do so.
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