At the moment you have no redundancy, so I can’t really recommend anything!!! You are currently already at the point where if any of the storage devices die, there will be data-loss!!
Mini-PCs are generally not great for storage capacity, and it seems you are at your limit - took a look and this device doesn’t have thunderbolt or an exposed PCIe slot so you are most likely out of luck.
Remove data from your system? That’s kind of an obvious answer, but it’s really the only one there is–other than moving to hardware that better suits your use case.
Just in case you wanted to hear it again, your system is not setup correctly unless you are fine with no redundancy. USB drives are discouraged. You can use them to import/export data but should not use them as part of a pool/vdev.
My recommendation: Buy a new set of hardware suitable for TrueNAS to run on or you can switch over to other NAS software that will be better for your hardware and that could use USB, but it should not be a ZFS structure.
EDIT: After reading this many hours after I wrote it, I feel like I came across wrong. “Just in case you wanted to hear it again” in my mind was “If you wanted to hear it again from a person with possibly a different opinion”. I was not trying to be mean. While in my mind I know what I think I’m conveying is good, in reality that isn’t always the case.
You need to make room, 80% of less of space usage.
Once you make more room, you need to then either get larger drives, or create pools with similar sized drives, you may want to consider just buying spinning rust drives and not use SSD’s if space is what you need.
The OP have one of those small hand-held ultra-small computers that generally run Windoze, no physical space for more than an NVMe M.2 card and a 2.5" drive I believe. I have something similar for my main computer, but it is a bit larger, but can’t use a 3.5" drive, well if I were to, I’d have to create my own drive bay to mount it to. I can shove in it a few M.2 and 2.5" drives.
I understand what you are saying, and I deeply regret investing in such a „closed-off“ system.
Please bear with me…
The majority of the data I have on this system are, unfortunately, old movies and TV shows that I manage with Sonarr and Radarr which are installed on the TrueNas.
Is there any way that I can put all these files on an external USB disk and continue managing them with the Truenas?
What would be the most efficient way to do that? (I have a Fritzbox 7490 and a Raspberry 4b at my disposal)
I’ll play devil’s advocate here to say that it will probably work ‘to an extent’. You could use a USB-SATA adapter to connect your drive and it would probably be fine, though what I can say is that it will not be fast and you could run into any number of unexpected issues.
Personally I wouldn’t recommend it. Thunderbolt? Maybe. USB3.0? Probably not.
At the moment you probably don’t want to be ‘expanding’. You’ve got two storage devices, each with no redundancy, in their own pools. If either of those storage devices die you will lose all data in that pool. As you mentioned most of these are TV/Movie media, perhaps it isn’t the end of the world if you lose these, but consider whether or not it’s something you can tolerate.
I would either buy two much larger storage devices (though probably difficult to do in your form-factor) and then migrate to a single pool with a pair of mirrored devices, or switch to a larger form-factor capable of properly supporting more storage devices.
The problem is that this mini-PC is already at capacity… 2x 2TB, that’s it.
I have no problem losing the movies and tv shows (although there are a few 80ies that are difficult to find now). Hence, I would like to put them on another drive, and, if possible, continue to manage them with TrueNas.
Are you certain? I saw the specs for the device and while it did state 2TB was the capacity, it also said it comes with Windoze. Maybe Linux would not have that limit. However a 4TB M.2 drive is I would think cost prohibitive for movies and TV shows. My thought here (Stressing my thoughts and what I personally would do because I don’t mind taking a small risk like this, and I stress that this is not to me worth the cost of storing Movies/TV videos):
Purchase a single 4TB (or larger, at your own risk) SSD.
Power down the system.
Remove the SSD and install the new SSD.
Create a new pool (I would call it tank3).
If the capacity is now the full size of the SSD, you have a working device.
Now for the fun part:
Transfer all the data you have from tank to tank3.
Shutdown and remove the new SSD.
Reinstall the original SSD.
Power up and transfer all your data to the NVMe drive.
Power Down.
Swap the SSDs again so the new one is installed.
Power on and transfer any data you desire to tank3. You should have less than 80% used capacity however that is in a normal setup, I’m sure you could just move to 94% and be fine.
Of course, all this banks on the fact that the computer can utilize greater than 2TB SSDs. If you have a possible second use for the higher capacity SSD, just in case this doesn’t work, then it isn’t a high risk other than it having no redundancy.
And after reading this back, I’d look into buying two 8TB NVMe drives and making a mirror to add redundancy. But first I would need to find out if there is a possible hardware limitation from 2TB to 8TB for M.2. I can’t think of one but then again, I have not investigated it. Maybe the company that makes the computer can tell you if you contact technical support.
As @essinghigh said, you can do that using USB, and it may work well. It also may not work well. This would be a single stripe drive, which is fine however high risk. Aslo, many if not all the External USB 2.5" drives are SMR. Storing data is fine, rewriting data comes with a cost and too much could mean the pool dropping.
I still recommend buying new hardware and setting up a proper TrueNAS machine.
My suggestion would be to buy 4TB NVMe drives, assuming they fit your mini-pc, and then run them in mirror in order to have redundancy… but it appears you can’t do that.
Which means you can only use 2TB NVMe drives in a stripe if you really want to have max space and have no concern about losing data… but be aware that losing either of them will make you lose all the data: this could be addressed with a monthly backup to an external drive.
Do not use external HDD bays since those have RAID controllers in them that will give you trouble with ZFS, even in JBOD mode.
I wrote to the support of the mini-PC, and they said 2x 2 TB is max. I could probably try it out anyway, but as you‘ve mentioned yourself, the cost-benefit ratio is off.
I‘ll probably take my Raspberry Pi 4b and use it as a nfs-server, plug in a 4 TB usb drive and put all the movies and tv-shows in there. If it dies, so be it. At least it doesn’t take down the Truenas with it.
If at some point in time you find yourself with a 4TB drive that you could install just for testing purposes, then you could at least verify it. I’m certain the RPI will be fine.
