I currently have a Terra-Master F4 424 Pro, (i3 N305, 32gb ram, 4-bays, 2 nvme slots) running Teraa-Master's OS and I've been thinking of switching to either Unraid or TrueNas. In trying to figure out what might be the right direction for me I was wondering what would be the best way, or ways, of setting up the drives that I currently have. Use wise, currently its mostly for media storage, some form of player like Plex or Jellyfin, and storage of backups of local computers. I currently have been messing around with Home Assistant run through Docker there, but I'm unsure if I will keep running it. ZFS sounds appealing in regards to "self-healing" files and ensuring bit rot doesn't kill something like an old photo that I've been keeping, etc. but I'm pretty new to all of this (one of the draws towards Unraid over TrueNas is it's reported ease of use over the other).

One of the 4 WD Red Pro 14tb drives I have already reported SMART failures with it being under 2 years old and having spent the last 8 months or so sitting on a shelf after I migrated the system to TOS 6 and had to rebuild the arrays (went down from using all 4 at once to using just 3. I had been holding onto it more of as a spare or if I needed more storage, etc.

So the system, now running a version of TOS 7, is using 2 Kingston KC3000 2tb nvme drives and 3 14tb wd red pro hdd drives in Terra-Master's take on a hybrid array (where it's supposed to move things on its own between the two types).

Which leads to the actual question, of how you would configure 3-4x 14tb hdd's with 2x 2tb nvme ssd's in unraid?

Reading through the documentation on ZFS it sounds like I might want to consider ignoring having an pool (I may be mixing up the terms) and the 3 hdd's in a raidz1 and the 2x nvme in a mirrored array, with the intent of storing only say apps and similar on the ssd array. Is this the right direction, perhaps adding the 4th drive when it gets back from warranty replacement as its own zfs array and using it as a replication target for backing up the other 2 arrays. Going this direction though feels like I'm ignoring one of the big features of Unraid, as I'm not just adding all of the drives together into a pool.

Any feedback or advice is appreciated. Thanks.

You are getting the "terms" backwards from our perspective.

The "array" is the individual disks protected by separate parity disk(s) using Unraid's implementation of parity. There is only one array. The array is optional on recent Unraid versions. The array is for HDDs and they don't have to be the same size but none can be larger than parity. XFS is the default filesystem for the array disks but others are allowed.

"Pools" are disks assigned outside the array. There can be zero or more pools, each can have one or more disks. Usually SSDs are used in pools, but HDDs are allowed. Multdlisk pools must be btrfs or ZFS.

User Shares are the combined contents of array and pools. This is how Unraid allows folders to span.

So what does that mean with regards to suggested configuration?

Do you have a backup plan? A single copy of your important and irreplaceable data isn't good enough no matter how that data is stored.

So primary data relies on individual pcs. Then 2nd copy is stored locally on nas. Offsite is currently various cloud services to later be unified eventually. Ripped media that can be reripped, streamed via a service, etc. is really the only data that doesn’t follow that because it’s relatively easily replaced/recreated.

This is a home network. Part of the hoped for goal of the nas is to unify the 2nd local storage instead of various thumb drives, external drives, old pcs, etc. to one place. Then that location can make it easier to backup to a specific cloud storage instead of iCloud, Dropbox, Google Drive, OneDrive, etc. that individual devices may currently use.

While I appreciate the desire to make sure I’m thinking beyond “raid as a backup “, I’m not really following how this question relates to drive configuration. If it’s supposed to, further explanation would be great.

Now back to how would this pool(s) configuration(s) recommendations would be appreciated.

Edited April 30Apr 30 by WhatNoise
Baby interrupted original posting, needed to elaborate

HDDs in array, with one as parity. Data disks formatted XFS

SSDs mirrored pool, ZFS or btrfs, might as well name the pool 'cache' but will be used for Docker/VM related shares also.