Hi! Thank you for your answer.
I’ve seen that link but it doesn’t really answer what I am really worried about. Have a look at this post in the forums. It’s old but I cannot see that anyone have concluded that it actually works at any point. The problem they are talking about is a really old resize2fs on the pr4100. According to the Ubuntu forum that is referred to in that thread, resize2fs needs to be at version 1.43 or later to be able to extend a volume beyond 16TB. I have a PR4100 with the latest firmware and my resize2fs is still at v1.42.9 - from Dec 28, 2013!
I would very much like to know if I can extend my current volume by replacing all the disks AND keeping everything on it. Maybe it’s not an issue anymore, I don’t know but I would like to know before a buy 4x10TB disks.
// Robert