QuotaAdvisor NT, Enterprise Edition

Every systems administrator knows that when you add user storage space to your network, users' storage needs instantly expand to consume your new disk. One of Windows NT Server 4.0's major drawbacks is that the system does not have built-in quotas to prevent user abuse of storage privileges. QuotaAdvisor NT, Enterprise Edition, from W. Quinn Associates solves NT's storage space problems. QuotaAdvisor lets you generate reports about users' disk consumption, identify large-consumption users, and implement a series of controls that limit user storage.

Installing QuotaAdvisor took me about 5 minutes. The installation process was straightforward, but I needed to reboot my server before I set up my quotas. To set quotas, you can use the command-line utilities with a new-user-creation automation script, or you can use QuotaAdvisor's GUI quota management utility, as Screen 1 shows.

Planning a Policy
The most time-consuming aspect of installing and setting up QuotaAdvisor is formulating disk usage policies. If you don't have experience with operating systems that allow quotas, QuotaAdvisor's documentation will walk you through the steps you need to effectively plan your quota policy.

When you install QuotaAdvisor, you can set up three types of quotas: default quotas, perm quotas, and overdraft quotas. A default quota limits overall use of a disk, directory, or file. For instance, by defining the default quota as 95 percent on a 4GB disk, you can prohibit storage on that disk from exceeding 3.8GB. You can also use default quotas to prevent a specific directory or file in a shared environment from getting too large. You can exclude certain users, such as administrators, from your default quotas.

A perm quota limits the amount of space a user or group of users can take up on a disk or within a directory. For example, you might assign a 10MB perm quota to a user's home directory.

An overdraft quota is a safety mechanism that lets users temporarily take up more space than their perm quotas allow. Overdraft quotas protect users from losing data because of storage limitations. You might give users who have perm quotas of 10MB an overdraft quota of 2MB so that they have an absolute maximum of 12MB of storage.

Quota Enforcement
To implement a quota policy, you must define the file, directory, or disk on which you want to set each quota and establish whom you want the quota to affect. Each quota can apply to one user, several users, a group, many groups, or a combination of users and groups.

Then, you must set up an enforcement policy for your quota. You can set up QuotaAdvisor to take one of three actions when a user exceeds the quota. First, QuotaAdvisor can terminate the user's storage privileges immediately, so that the user loses any data in excess of the quota. Second, QuotaAdvisor can save the data created by the I/O operation that takes the user over the quota and then terminate the user's storage privileges. Third, QuotaAdvisor can monitor the user's storage habits without interfering with the user's activities.

QuotaAdvisor also lets you set up to five threshold values, measured in percentages of a user's perm quota, that trigger the software to take action. At each threshold you establish, QuotaAdvisor can send a message to the NT event logs or to a user, execute a command (such as NET SEND, which sends the user an interactive warning), or generate a report about the user's quota usage. For instance, you can set Threshold 1 to 50 percent and require QuotaAdvisor to send notification messages to users who reach Threshold 1. If users have perm quotas of 1MB and use 500KB of disk space, they will receive a warning that they have used half of their allotted storage space.

QuotaAdvisor provides a nice solution to NT user storage problems, and I found that the software works very well. I recommend QuotaAdvisor for every large-scale network administrator's toolbox.

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