Windows Server 2008 supports an enhanced quota management system called Resource Manager Disk Quotas. Using Resource Manager Disk Quotas, you can manage disk space usage by folder and by volume.
Because you manage Resource Manager disk quotas separately from NTFS disk quotas, you can in fact configure a single volume to use both quota systems. However, it’s recommended that you use one quota system or the other, rather than both. Alternatively, if you’ve already configured NTFS disk quotas, you might want to continue using NTFS disk quotas on a per-volume basis and supplement this quota management with Resource Manager disk quotas for important folders.