i may have shot myself in the foot by adding a dedup device to my pool without understanding what i was doing. now i can’t seem to remove it, even though it’s unused. (no data set has deduplication enabled.) my configuration looks like so: # zpool list -v data …

Sorry, I am not aware of a way to “save” the dataset configuration specifically. There’s the TrueNAS config of course, but that’s not quite what you’re after here. While I haven’t tried it myself - shares appear to reference data using basic paths. So presumably you could disable the shares before …

Next time make a checkpoint before adding a new vdev to your pool.

There really really really need to be some “You are about to add a DEDUP vDev to your ‘data’ pool. THIS WILL BE PERMANENT AND CANNOT LATER BE REMOVED. Are you sure?” messages in TrueNAS. @kris @honeybadger

so, backing up my data to a different device then deleting / recreating the pool seems to be the thing to do. of course, i don’t have another five terabytes of networked RAID just lying around unused. but i DO have a USB disk large enough, and for a temporary procedure it’d do. now how do i get Tr…

You don’t. You connect it to a client and transfer the data across the network.

But if you could, a locally connected 12TB USB disk with a ZFS pool on it could then use replication to copy the data.

this was precisely my plan, but for some reason it isn’t seeing the USB disk. and the TrueNAS box is running headless, so it’s a slight pain to diagnose. i may have to connect the USB disk to another machine on the net and run an rsyncd to receive the data. such a bother.

I would expect the disk to show up as available for creating a new pool. Once you resolve that, you replicate everything across, then destroy and recreate the other pool, then replicate back.

after resolving an ID10T error relating to the disk itself, sure enough, it was recognized. after that, setting up the replication task was a simple matter of trying and failing enough times to make me read the fine manual. then fine-tuning the task after i got it set up, so that it’d target the per…

[image] Lynx: i’d like to have this spurious NVME dedup device removed from the pool before i actually try to use deduplication, if possible. help? Mind that deduplication is a resource hog, requires at least 64 GB RAM as a start, and is generally not worth it for home use. But if you’re sti…

Removing a device i shouldn't have added to pool

TrueNAS General

winnielinnie September 18, 2025, 1:54pm 19

If only the OP asked “Should I add a dedup vdev to my pool?”

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Removing a device i shouldn't have added to pool

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