As you regularly back up your data (daily) using the Backup Manager, a series of backup sessions accumulate in the Cloud (your remote storage location), and on the LocalSpeedVault if this is used. After a certain period (typically 28 days), older sessions are cleaned (deleted) to free up storage space on both the remote and local storage locations. The duration of the retention period is variable and measured in days. You can specify your own retention period, or maintain the default of 28-days.
If needed, you can keep selected backup sessions in the storage after their retention period expires using the Archiving feature. Such sessions will not be deleted (unless you choose to do so manually).
If data is removed from the backup selection, any future backups will not include this information, but all versions of this data stored in an Archive session will not be affected and so will be kept until a clean is done of the archive sessions.
If LocalSpeedVault is used while Archiving is enabled, the used storage of both the Remote storage location (the Cloud) and the Local storage location (LocalSpeedVault) will increase.
https://documentation.n-able.com/covedataprotection/USERGUIDE/documentation/Content/backup-manager/backup-manager-guide/archiving.htm