The way to resolve this particular tragedy of the commons, like most other such cases, is to privatize the commons: make people pay for the disk space they use.

The way to resolve this particular tragedy of the commons, like most other such cases, is to privatize the commons: make people pay for the disk space they use. If you want a nice big balloon.txt file to reserve space for the future, fine, but you're paying for the space you reserved. How you use it is up to you. In return, the administrators get both the money and incentive they need to buy more storage capacity, ensuring that running out of available space will be less of a concern.