SmarterMail provides an easy to generate a report showing how much disk space is being used for email on your server between all of your domains.
Log into SmarterMail as ‘admin’.
Once logged in, navigate to Reports, and then click Disk Usage.
Select whether you wish to sort the report by Domain Name or Space Used. For now, let’s choose Space Used. Once your preference is selected Generate Report.
You should now see a bar chart showing the total space used by each domain, a list below of the exact number in Megabytes of how much space is being used. As you can see, there is currently only one domain on this server and only 1 KB of space being used, but as more domains are added, the more comprehensive the report will become.