I recently lost my pool due a failed drive and replaced the drives and have a new pool I created. Now I am running but getting errors on my USB. I want to upgrade to 11.2 and I have downloaded the ISO. Before I upgrade, should I detach the volume or leave it as it and upgrade on the fly? I worried about loosing all the data I put back in the pool. I want to reformat the USB before the upgrade but worried any ZFS or Zpool information needed for the volume on the USB stick. What should I do?