[netsharc]

Are there many tiny files? They may take 4KiB of space each even though they're less than a KiB big (https://en.wikipedia.org/wiki/Disk_sector).

On a SanDisk portable SSD I own, the cluster size is even 4MiB. If you put a node modules directory in there with thousands of tiny files, it can "take up" several GiB of space.

[bombcar]

This can be an important reason to enable compression (on some file systems it “solves” the problem) and why virtual machine file format can be important.