Is there a way to make a file "append only"? I've lost some logfiles that got overwritten when I wanted them just to be appended. I know with NTFS there are detailed permissions that can be set, but ...

I have two TrueNAS boxes and a Proxmox host (call them boxes A, B, and C). I want to get them to replicate ZFS snapshots to a third TrueNAS box (call it box D). However, I want it to be as locked down ...