Before you read the title and roll your eyes, I've already read all of the various answers, posts, and articles that say you can't shrink a pool once you've made it. However, I saw this post which claims to do exactly that (i.e. remove a device from an active pool and shrink the pool to use the remaining disks). I tried to do it on my storage host and got this:
root@file2:~# zpool remove datastore sdh cannot remove sdh: only inactive hot spares, cache, top-level, or log devices can be removed
So, I'm guessing I'm using an older/different version of zfs. Does anyone have experience with using this functionality? Am I totally wrong and it's still impossible?
If it matters, I'm running Ubuntu 15.10.