Truenas scale import pool

TrueNAS General
1

I’m working with Truenas Scale v25.04.0 and need to import a exported pool.

This seems easy as the UI allows importing, but at the point of the import, it asks for an existing pool to import or the option of creating a new pool.

Here’s the problem: If I don’t have an existing pool, because the only drives that exist have an exported pool, I cannot confidently import because I don’t have an existing pool, and creating one up import tells me “The following disks have exported pools on them. Using those disks will make existing pools on them unable to be imported. You will lose any and all data in selected disks.”

Now that’s a problem. Do I need to have an existing pool to import the exported pool into, which would require adding empty disks with a pool defined, or could I, somehow, import the pool without need new disks with a pool available?

2

I do not have a 25.04 system to test this on, but I suspect what it means by

is should it import the exported zpool that exists on the disks or create a new zpool using those disks.

I assume you are clicking on the import pool button at the top of the Storage Dashboard.

3

If you import the exported pool, it doesn’t go into another existing pool, it just becomes present on the system.

So if you have a pool called tank, export it, and then later fresh install TrueNAS with the same disks, you’ll have no usable pools but your disks will have an exported pool called tank on them. When you click Import Pool and select tank, makes tank an active, usable pool on the system. So now your system has one pool called tank.

If you choose to create a pool using those disks you’re creating an entirely new pool, erasing any data on the member disks.

4

Thanks for the reply.

So, following you advice, I plugged in the exported pool drives and simply booted. Now the pool is back without any importing necessary. That doesn’t make sense. Why would, on a given boot, TN says there’s no pool except on the exported drives, and require an import, then on a subsequent boot with the drives attached, TN now boots showing the pool without any need to import.

I’m happy with this result, but I didn’t export the pool in the first place, but TN thought I did.