In a mixed environment, users can log in as either Windows users or UNIX users. You can configure quotas to recognize that a user's UNIX id and Windows ID represent the same user.
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How you map names using the same quotas file entry
You can map Windows to UNIX names by putting them together in the same entry in the quotas file. However, this requires a quotas file entry for every user.
How you map names using the QUOTA_PERFORM_USER_MAPPING directive
If you have configured the system's /etc/usermap.cfg file with a one-to-one correspondence between UNIX names and Windows names, the QUOTA_PERFORM_USER_MAPPING directive in the quotas file automatically links the names. You do not have to add a separate entry for each user.