It is common for administrators to store multiple versions of files, allowing the end-user to restore an older version if the latest version is corrupted. Consider the following example, when this is very useful.
By default, Syncrify stores previous versions as deltas - meaning the most recent version is stored in its entirety but only binary changes are stored for previous versions. In most cases, only a fraction of 15GB is modified on a daily basis, and therefore, older versions will consume a fraction of disk space.
Starting from v5.4, Syncrify server displays the amount of disk space saved by storing the previous version of files as delta.