Outlook Backup uses separate storage to keep the PST files, which is located on the FTP server and not the Exchange server. The storage disk space used by PST files created by schedules or one-time backup is included in Outlook Backup Disk Usage. 

Note: The amount of disk space available for the account depends on your plan. You can check this by navigating to CONTROL PANEL > Services > Outlook Backup > Storage Management > Disk Space Included With Plan

Used Storage

In CONTROL PANEL, navigate to Services > Outlook Backup > Backups to review and manage existing backups on the account. PST file size is calculated once a day during maintenance. After a new backup is created, it might take up to 24 hours for the correct size to be displayed.

To view the overall used storage, navigate to Services > Outlook Backup.

overall storage

FTP Access

You may also view the existing .pst files and their size using FileZilla FTP client. Read the Knowledge Base article How Do I Use FileZilla To Upload/Download Multiple PST files? for connection instructions.

Important: Only Account Contacts with Technical Administrator role and Outlook Backup service assigned can use their credentials to access FTP servers.

Once you are connected, in the Remote site area, expand the root directory ("/") and click the folder with the name of your Exchange account and then Upload subfolder. In the section below the folder list, you will see the files on the server along with the filesize.

ftp

Note: You cannot DELETE PST files from the FTP server using FileZilla, please use CONTROL PANEL for that instead.

Additional Disk Space

If the disk space is exceeded, additional disk space will be added to your account automatically. Account administrator will receive a notification on this.

Additional amount of storage will be charged to the account after 5 days of being over the limit. In this period, you may download the PST files and remove them from the system to avoid extra charges. 

If disk space was removed, Purchased Additional Disk Space will not be automatically adjusted. To lower the additional disk space, navigate to Storage Management in Outlook Backup, then change the dropdown menu for Purchased Additional Disk Space to 0 and click Save Changes.

additional

Note: You may need to wait up to 24 hours after deleting PST files before the storage space will be recalculated and you will be able to lower the additional disk space.

Retention Policy

If you use regular scheduled backups, you can set up retention policies to avoid exceeding storage limits by removing unnecessary PST files. To do this, navigate to Services > Outlook Backup > Create Backup. After you adjust the settings for the backup, choose one of the options for the retention policy.

retention