Thanks everyone for helping me with this problem.
I decided to move all data to another pool (no SMR drive) and remove those drives from the server.
I will mark this as Solved.
Sadly even non pro ironwolf are 7200RPM very noisy and high power consumption compared to WD, I think they just throttle to 5400RPM performance in firmware but still fast spin.
WDC red 'plus' and 'pro' are ok, they not SMR, but avoid the standard...
Do you expect a connection error and not the probably very old 2TB WD red drive?
VRPF failed, right?
You pulled it out and inserted the 9TN2, right?
BTW don't do that if you have enough bays. Just insert the new drive and let the resilver do...
Iirc WD20EFAX are SMR ("Shingled ..."). It is really a game of luck to make them work with ZFS. (Read https://www.truenas.com/docs/hardware/notices/wdsmr/ )
Problems especially during resilvering are somewhat... expected.
Yes you are absolute right, @UdoB, @andretona don't use WD EFAX Drives.
it's about 6 years ago, a setup a mdadm mirror/ raid1 setup with these WD EFAX and they failed soon.
# https://www.truenas.com/docs/hardware/notices/wdsmr/
#...
One of the disks was marked as having too many errors, and after as removed.
I changed the drive with an identical one and used the command zfs replace, but during the resilvering process, the new drive started getting errors and being...