Using USB Thumb drive to run as boot volume Truenas Scale

So I started with my truenas with an old 128G SSD as boot volume.

Want to mirror it to give a slightly extra-redundancy but a bit waste of using another SSD…

Thinking to install again with USB Thumb drive (may be something like 32 GB) and then mirror it with another USB Thumb drive…Though …:

  1. As advised from doc SSD is recommended as swap file will be constantly write to boot volume. What if I don’t create swap during the installation? So does it mean the I can use USB Thumb drive without match issue as only initial load read and sometimes read write which changing config?

  2. What will be the trade off without swap? If I only use it for file shares and have enough ram would swap even matters?

I used to use dual USB drives to boot my TrueNAS systems and though it worked mostly without issues, they did wear-out extremely quickly due to the various writes that happen as part of normal operations to the OS disk(s) regardless of SWAP. I also do not think you can not create a swap as it determines during install if SWAP is created based on the size of the disk(s).

I ended up getting a pair of small SSDs (Kingston 120 GB) drives for each system and also dual SATA to USB adapters for each system and things are much better.

The only reason I still use the USB to SATA adapters is because I am re-purposing 3 older QNAP devices and I did not want to lose 2 of the 4 drive bays to the OS disks.


For home use, don’t bother. It’s fine if you don’t have money on the line tied to the uptime. Any half-decent SSD will last forever in this role.


When I first upgraded to scale, I still had my dual usb thumb drives in play.

It worked. It nagged me. The perf sucked.

I switched to a boot SSD. Perf improved.

Later I added another drive as a mirror. You can skip that if you want, just ensure you have a config backup. Preferably setup some config backup task.

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Oh… config back up task? like a scheduling task? I couldn’t find any config task back up scheduling …

The functionality is built into Multi-Report. Maybe set that up?

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i second what stux said.

also when i was testing my backup/recover,

so even if something did happen to the boot drive, i wouldn’t be too worried, because i can replace that if necessary of ssd gone bad or something with the usb external enclosure for the m.2 nvme ssd.

because upon a new truenas reinstall for the boot drive, you can import the saved working truenas config.

and also import the pools you created without losing your data.

having tested the recovery process myself that is why i’m not too worried about it.

though ideally people do recommend a mirror for your boot, if possible but if not then even a single drive boot is ok afaik.

I guess I must be lucky. I’ve been using the same 60 GB SSD I first used for the last 10 years. Honestly, I see very little point of mirroring the boot drive other than wasting an extra drive and an extra SATA port for something that can be easily recovered in 5-15 mins of work if you don’t mind the downtime.

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You do not need an SSD boot device, but we discourage using a spinner or a USB stick. We do not recommend installing TrueNAS on a single disk or striped pool unless you have a good reason to do so. You can install and run TrueNAS without any data devices, but we strongly discourage it.

i’m not calling you out or anything, i also use a single boot drive, and some mirror boot drive. i use both types for different nas depending what i have available at the time during setup.

but officially that is the recommendation. not just them, even other places may say something similar.

this is an interesting case study what happens and whether mirror boot pool is all it’s cracked up to be or not. maybe there is much more to it than just that, but interesting nevertheless

i think eric summed it up nicely

but back to the original question

Using USB Thumb drive to run as boot volume Truenas Scale

No. you definitely shouldn’t use usb flash sticks for that. Usb external enclosures e.g. m.2 nvme ssds which is what i use for a truenas boot drive are fine

Avoid using USB-connected hard disks for primary storage with TrueNAS. You can use USB Hard Disks for very basic backups in a pinch. While TrueNAS does not automate this process, you can connect a USB HDD, replicate at the command line, and then take it off-site for safekeeping.