[spindle]

I use external disks (not a NAS), with ZFS. Everything gets backed up to two separate disks. ZFS snapshot replication makes backing up very fast, and ZFS can also check for bitrot.

I use my own simple backup script ... for a Hacker News person, it's a toss-up whether it's easier to write your own script or learn a high-level interface like sanoid/syncoid.

As for RAWs, I use a system more or less like yours, but I store my best photos separately from the others, which solves the filtering problem you mention.