Thecus N2200XXX User Manual page 167

The framework keeps track of the total amount of data a user has used across
different folders and functions such as the photo server.
Please do enable the user quota function first. Then you could choose "Sync" to
calculate for all of users to each associated RAID volume with used space.
NOTE
To setup user quota, simply click on desired user with associated "Quota" filed then
input numbers. Left default value "0" with no quota limitation for associated users.
Please be sure the "Apply" button has confirmed for changes.
Please do execute "Sync" if user quota has been disable then enable
again to make sure the accuracy of quota used for each user. Or the user
used capacity will not count during user quota function is disabled.
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