I'm trying to run a load of services and use TrueNAS Scale as the data storage for them. I have three 1 TB disks setup as RAIDZ1 - a single data pool. I've had to unplug the power a few times for various practical reasons and it seems like this setup simply cannot be relied on to function. Sometimes it's fine, sometimes it's not. I feel like I'm taking crazy pills here and cannot for the life of me figure out what I'm supposed to be doing.

I take a look at the storage dashboard and see "Unused disks: 3". Okay, let's add them back to my pool ("main"):

Add Disks To:

• New Pool
• Existing Pool

...except there's no pools listed under "existing pool". If I create a new one it just wipes the disks. That's no bloody good.

Thankfully I've yet to store any important data on them as I'm still in the testing phase. As far as I can see though, despite the disks being attached to the system by serial number, it gets confused and doesn't keep them through power disruptions.

Is it worth fannying about with TrueNAS? I feel like I might as well just bin ZFS and use an rsync-based backing up of data (I have several other disks, but only three that are the same size).

Okay so when you say “unplug the power” do you mean shut it down first or just pull the plug? The latter is a great way to corrupt your storage pools as ZFS uses memory for read and write cache etc by default. You definitely need to do a graceful shutdown especially if there is data that was recently written to disk, that’s why a UPS is so recommended. That said you can usually import an existing pool when that happens, I think there is a UI menu for it now.

The hard disks are on a separate power supply. The TrueNAS software is running on an old laptop so it effectively has UPS protection.

Okay so the disks aren’t also on UPS? That might actually be even worse than the whole thing getting turned off, ZFS is definitely not meant to be run on removable disks like that.

Haha, yeah. It does make me wonder whether I should bin the whole TrueNAS approach entirely. It seems like a tremendous faff when I could just have the files mirrored to another disk as a backup.

If you shut down the computer gracefully first before you power the disks off it should be ok more often than not, but you really should try to have everything on the same system so this can all be coordinated by the OS and the hardware.

As others have said, avoid powering the disks off before the OS has had a chance to shut down or your disks will NOT be in a recoverable state when everything comes back online.

I’m not even sure the setup you are describing would benefit at all from a different storage method, even “regular” writes could be in memory or controller buffers. External drives are not meant to have their power cut.

These are internal drives connected to a desktop PSU wired to a USB interface to connect to the laptop.