Drives added to mirror, but mirror not extending?

[chefjaytay]

I have a 2 drive mirror (14TB drives). I am hoping to extend it to include an additional 2 drives. I clicked to extend them into the Pool, and the system resilvered, twice, for 12+hrs each time. No errors and no alerts. The drives obviously show up in the interface as I was able to select them to extend the pool. After resilvering, it shows the disks, however the pool shows the same available space as original 2 disks? I have rebooted the NAS system with no status change.

 

[NugentS]

My suspicion is that you now have a 4 way mirror, rather than 2 vdevs of 2 mirrors

zpool status, in code blocks - indents matter please.

If I am correct I believe you can remove the two additional mirrors and try again by attaching a new vdev of mirrors