Adding a volume to your Rcs.is doesn’t increase its main disk. Instead, it adds on a second disk as a second partition. To expand the Rcs.is’s main disk, you need to resize the Rcs.is to the next plan.

If you need additional storage, you can either add a new volume to the Rcs.is and move some files to that volume, or configure all the logs in /var/log/ to save directly to the new volume.