Hello Ricardo, > Should we attempt to overwrite /gnu/store and rely exclusively on > substitutes from the cache? Yes, I don't see any other options. Before that, what might be nice could be: 1. Ensure that all Berlin /var/cache/guix/publish directory is synchronized on Bordeaux. We are now at 117G out of X. We could then start a publish server on Bordeaux. As Bordeaux is already part of the default substitute servers list, the transition could be smooth I guess. 2. Determine what file-system out of ext4, btrfs and xfs could be the most suitable for Berlin's /gnu/store. I'm running some tests on an old HDD to try to determine the fragmentation impact on those file-systems. We can of course choose to be conservative and go for ext4 that did the job until now. Regarding the /gnu/store re-creation, I wonder how can we do it without reinstalling completely Berlin. Maybe we could save the system store closure somewhere and restore it on the shining new file-system? Thanks, Mathieu