Windows 2000 first introduced the disk-based quota feature, allowing an administrator to define a limit or set of limits on the consumption of disk space by individual users. Windows Server 2008's quota management features some interesting properties:
Windows Server 2008 can distinguish between volumes, so you can set different quotas on different volumes to perhaps segregate types of data, or to offer a disk exclusively to a set of users for their daily work.
You can assign disk-based quotas on mapped drives as long as the physical volumes to which the mapped drives point were created with Windows 2000 Server or Windows Server 2003 or were upgraded to either of the later versions from Windows NT 4.0.
Unlike some third-party software programs, Windows Server 2008 does not allow grace writes. That is, some software allows a user to continue an operation—say, a file copy process—even if during the middle of that operation the disk-based quota is reached. Windows Server 2008 does not allow this; it will cut off the operation when the quota is reached.
As usual, though, neat features always contain weak points. First, quotas are supported only on disks formatted with the NTFS filesystem. This isn't too surprising because most progressive filesystem features aren't available under the various flavors of FAT. Second and perhaps more disturbing is that, due to an architectural limitation, disk-based quotas (those assigned on the volume level, that is) can be added only to individual users. This creates quite a headache, as most other network operating systems allow you to set a default quota based on group membership. In this manner, all normal users could have 500 MB, power users and executives could have 1.5 GB, and administrators could have unrestricted space. Alternatively, payroll users could have 250 MB, while the sales team with their myriad PowerPoint presentations might need 1 GB a piece. Alas, Windows Server 2008 doesn't support this by default out of the box at the disk level, but later in this section I'll show you a problematic but workable way around this limitation.
To set up default disk quotas through Windows Explorer, follow these steps:
Open Computer, right-click the drive for which you want to enable quota support, and select Properties.
Navigate to the Quota tab.
Make sure the "Enable quota management" checkbox is checked. If it's not, quota support is not enabled. If you want to continue, check this checkbox.
Choose one or more of the following selections based on your needs:
- Deny disk space to users exceeding quota limit
If you check this checkbox, when users reach their disk-based usage limit, Windows returns an "insufficient disk space" error, thereby preventing them from writing more data until they either change or remove files to make more space available. To individual application programs, where this behavior is handled in various ways, it appears that the volume is full. If the checkbox is not checked, users can exceed their disk-based quota limit, which makes this an effective way to simply track disk usage by user and not enforce limits on storage space use.
- Limit disk space to
Here, specify the amount of space newly created users of the disk can fill, and the amount of space that can be used before alerts are recorded in the event log (known as the soft quota, or warning level). You can use decimal values and varying units to fine-tune your settings.
- Log event when a user exceeds his quota limit
If quotas are enabled, disk event entries are recorded hourly in the system event log when a user reaches his hard quota, or official limit.
- Log event when a user exceeds her warning level
If quotas are enabled, disk event entries are recorded hourly in the system event log when a user reaches her soft quota, or warning level.
You might find it useful to set individual disk-based quotas for specific users that exempt them from a more limiting default quota you might have configured. You can set these individual quota entries through the GUI by clicking the Quota Entries button on the Quota tab under the Properties sheet of the disk in question. In the Quota Entries for Drive box, select Quota from the pull-down menu and click New Quota. Figure 3-32 shows this.
Select the user to which to apply the new disk-based quota, and in the box, configure the restrictions on the user's space.