Platform SDK: Files and I/O

Disk Quota Limits

The disk space used by each file is charged directly to the user who owns the file. The owner of a file is identified by the security identifier (SID) in the security information for the file. The total disk space charged to a user is the sum of the length of all data streams. In other words, property set streams and resident user data streams affect the user's quota. Compressing or decompressing files does not affect the disk space reported for the files. Therefore, quota settings on one volume can be compared to settings on another volume.

The following are the types of disk quota limits:

NTFS automatically creates a user quota entry when a user first writes to the volume. Entries that are created automatically are assigned the default warning threshold and hard quota limit values for the volume.