Agreed you need a bit of pre-thinking going into this. - I don't see much activity on the root volume, most of it in my case is either from VMs or userland. -

Agreed you need a bit of pre-thinking going into this. - I don't see much activity on the root volume, most of it in my case is either from VMs or userland. - For VMs I use discrete subvolumes, different fs/snapshot/backup strategies given the intricacies of this use-case. You'd typically snapshot VMs from the hypervisor itself. - /home is its own subvol, with again specific settings. I typically disable COW on /home but adopt a much more agressive snapshot policy (e.g. every hour). Whereas system (/) can COW a lot with little to no performance impact, but snapshot only once a day is usually fine. Note that I only use SSDs (either 2x RAID 0 over SATA 3, or NVMe) and my workstation is a beefy one; so that may explain why I don't see any resource issue whatsoever with these admittedly heavier filesystems (btrfs being much leaner than ZFS in this regard, depending on how you setup the latter). My personal intuition is that major OS suppliers will eventually move to such 'modern' fs under the hood for most users, if only to provide easy rollback/backup features that actually work fine and fast. But it takes years to validate a new fs on an existing architecture, so I wouldn't expect that for Windows or MacOS until the next 'major' version (post-10.x, amusingly in both cases).