I used to back up with rsync from an EXT4 filesystem to a USB drive attached to the server:
rsync -aAXvr --progress --delete /boot/* /mnt/external-backup/t20/boot
Now I want to rsync to a NAS over the network, but I’m not sure how to set the ZFS dataset ACL type. I’ve read the TrueNAS ACL primer.
Two options:
- SMB/NFS4 → requires ACL mode passthrough
- POSIX → no ACL mode options
Since I’ll only use rsync (not SMB/NFS4), POSIX seems preferable.
However, ChatGPT and Claude recommend passthrough:
zfs set aclmode=passthrough pool/dataset
zfs set aclinherit=passthrough pool/dataset
zfs set xattr=sa pool/dataset # Store xattrs in system attributes for better performance
Which is the better choice? I’d love to hear your expert’s advice. If not, I’ll test by restoring to check ACLs, ownership, and extended attributes.