Rein in your space hogs
Network and systems administrators constantly fight the disk-space battle for network storage. Although disk space is fairly inexpensive, the administrative cost of managing large volumes of data can sneak up on an organization. When a file system becomes full, some level of administrative involvement—adding more storage, finding and deleting unnecessary files, or rebuilding a crashed volume—is inevitable. In addition to fixing the immediate problem, the administrator typically needs to identify individuals who consume more than their share of disk space.
Quota-management software takes a proactive approach to space allocation and removes the administrator from the enforcer role when users attempt to use more than their allotted storage. In this comparative review, I look at four quota-management products—WQuinn's QuotaAdvisor 4.1, Enterprise Edition; Northern's Quota Server 5.0c; NTP Software's Quota Sentinel; and Tools4ever's SpaceGuard 4.2—to see how well they manage disk space and how successfully they ease the administrative burden.
What's in Windows 2000?
Out of the box, Windows 2000 Server offers user-based quotas that you can apply to all users or a select group of users. However, as with many Microsoft OS add-ons, the feature's overall functionality falls short of what third-party products can provide.
The most noticeable limitation of Win2K's quota functionality is that it provides no directory quotas and no advanced notification tools. Directory quotas can prevent a disk from becoming full regardless of who writes files to it. Notification tools encourage end users to be proactive about their storage habits and relieve administrators from having to monitor event logs for quota violators. Win2K's built-in quota-management functionality might work for small organizations that experience minimal changes in disk usage, but if you're serious about effectively managing storage on your servers, you need a third-party tool.
The Test Environment
To test the products, I used four custom-built Intel Celeron-based computers. I installed Windows NT Server 4.0 on the first system, NT Workstation 4.0 on the second, Win2K Professional on the third, and Win2K Server on the fourth. Each server was a domain controller (DC) for its own domain, and I configured a two-way trust between the two domains. The two clients were members of both domains. This configuration let me test the products with Win2K and NT installed on both the client side and the server side.
To approximate the needs of a typical organization, I implemented identical quota schemes on both servers. On each disk object, I wanted to establish a quota to manage total capacity utilization. I gave each user account a 100MB quota on its home directory and a 50MB quota for the Files share on the server. In addition, I imposed a 200MB quota on each directory beneath the Files share. To test the products' usability in the arenas of quota implementation, management, and monitoring, I configured the same environment for each product.
Leading the Pack
QuotaAdvisor's features and stability lift the product above the rest of the crowd. QuotaAdvisor excels particularly in the flexibility it gives you for creating quota objects. Whereas most of its competitors require you to know the sizes of your partitions and enter an appropriate value for the quota size (e.g., in bytes, kilobytes, megabytes), QuotaAdvisor avoids the necessity of manual calculation and lets you use a percentage value to specify a quota size. QuotaAdvisor's most obvious drawback is the lack of detail in its instruction manual.
Quota Sentinel lacks some of QuotaAdvisor's flexibility, but I liked the idea of a hierarchical administrative model for managing quotas. Both Quota Server and SpaceGuard are reasonable tools for smaller organizations in which simplicity of administration is important. However, if that simplicity comes at the expense of a feature you need, you might compromise your satisfaction in the long run.
QuotaAdvisor 4.1
I installed QuotaAdvisor from WQuinn's StorageCeNTral CD-ROM. StorageCeNTral is a suite of storage-management products that also includes DiskAdvisor and FileScreen 2000. (Because I wanted to focus on quota-management features, I chose not to install these two products.) When I inserted the autorun-enabled CD-ROM in the Win2K Server computer, an HTML-based installation screen appeared, prompting me to select an installation of the Standard, Enterprise, or Cluster version of QuotaAdvisor. I clicked Enterprise. I then input my license key, from which the installation program determined that I was licensed to install the Enterprise version.
During the installation, the software prompted me for an account with administrative privileges that the QuotaAdvisor services could use. For this purpose, I created an account called QAServer and specified it (along with its password) in the installation dialog box. The software then presented me with options for configuring either a Microsoft Exchange Server or SMTP mail server for distribution of quota notifications to users. I created a mail account called QAServer on an Exchange Server system and specified that account in the dialog box. After the installation process installed the program files, I restarted the computer. An icon for QuotaAdvisor appeared on my desktop.
The Management Station
Clicking the desktop icon opened the QuotaAdvisor Management Station, in which the next phase of QuotaAdvisor's configuration occurred. The Management Station, which Figure 1 shows, is a centralized UI through which you manage and monitor quotas on all connected servers. The UI's left pane provides a treeview of the local computer and computers on the network. In the interest of productivity, the Preferred Machines branch lets you organize frequently accessed computers. The right pane displays the contents of the items that you select in the left pane.
The first time I opened the Management Station, the software's Management Wizard launched. However, I wanted to install QuotaAdvisor on my second server before performing any of the wizard's operations, so I closed the wizard. I followed the user guide's instructions for performing a push-install of QuotaAdvisor to my NT Server system from the Management Station, but the menu option I needed was shaded. I called WQuinn's technical support to determine the cause of this problem. After some troubleshooting, a WQuinn technician determined that I was experiencing a problem with one of the application's DLL files, which affected only QuotaAdvisor installations that aren't installed as part of the Storage CeNTral suite. I received a new DLL file and resumed QuotaAdvisor's installation on the second server.
The push-install resembles a local installation and gives you the option of restarting the installed server upon completion or delaying the restart until an appropriate time. Before running QuotaAdvisor, you must restart the server.
QuotaAdvisor Nomenclature
Before you implement QuotaAdvisor, you need to understand several components and subcomponents of quotas. To create a quota in QuotaAdvisor, you must first create a quota object. A quota object can be any physical portion of a disk, whether it's the whole disk, a share, a directory, or an individual file. To that object, you can apply an absolute quota, a user quota, or a group quota. You use an absolute quota to monitor and enforce disk-space usage regardless of users and groups. User and group quotas apply to an individual user or group, based on file ownership.
You can apply learn-mode quotas to users or directories. When you apply a learn-mode quota to an object, QuotaAdvisor scans the object and applies the quota settings to existing users or directories, based on the type of quota you configure. In addition, when you create a new user account or directory, that account or directory will inherit specific settings from any learn-mode quotas that apply to those objects. To ensure that files placed in lower-level directories apply to the first level's quota, directory learn-mode quotas apply only to first-level subdirectories. For example, if I place a 50MB directory learn-mode quota on a directory named \userfiles and create a subdirectory named \myfiles, the \myfiles directory would have a 50MB quota. Furthermore, if I create a subdirectory beneath \myfiles named \documents, that subdirectory wouldn't have a directly applied quota—rather, its contents would count toward the 50MB quota on \myfiles.