To view a report on resource usage by users and sites,Please follow the following steps :-
1) Login to Plesk control panel.
2) Click on "Tools & Utilities".
3) Do any of the following:
a) To view reports on the amount of traffic used by customers, click Traffic Usage By Customers.
b) To view reports on the amount of disk space used by sites, click Resource Usage By Domains.
c) To view reports on the amount of traffic used by domains (websites), click Traffic Usage By Domains.