How much of that data would mean the end of the world if it were lost?
For some of that data (perhaps Jellyfin containers, those test VMs) you may not need RAID at all.
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
How much of that data would mean the end of the world if it were lost?
For some of that data (perhaps Jellyfin containers, those test VMs) you may not need RAID at all.
Personal photos and videos. I will make external backups, but I prefer to have RAID and some fault tolerance (1 drive with RAIDz1).
Since this is a NAS, keep in mind Network speeds. A three drive HDD RAID-Z1 is going to have pretty fast read speeds. It won't saturate gigabit Ethernet but it will be fast. SSDs have will be able to saturate the network but you'll have a fraction of the storage.
For me I'd rather have the extra space and just wait a few seconds longer to transfer stuff. Since you're using ZFS you might consider a small SSD (no more than 1TB) as a ZIL. It'll speed up writes and help plug the write hole on the NAS.
That's exactly what I thought. Thank you u/giantsparklerobot :)
I've got a 4-disk RAID-Z1 and read speeds will come pretty close to saturating my gigabit Ethernet. My write speeds are a pretty consistent 60MB/s over the network. I'd really only go with SSDs if the NAS was an intermediary box that absolutely needed fast write speeds but then itself persisted to a larger but slower HDD box.
In general though I'm after storage primarily and speed second.
Great. Thanks!