In UMC, click Storage > User Quotas, and click ADD USER QUOTA.
On the VOLUME SELECTION page, search or browse the servers, select the required volumes from the list, and then click NEXT.
On the USERS & GROUPS page, search or browse the users and groups to list the users.
Select the user(s), specify the storage space you want to assign to the selected user(s), and then click NEXT.
Review the details and click FINISH.