I was on FreeNAS-11.2-U2.1 and experienced and issue where I could not delete an extent from the iscsi section.

This turned out to be a bug in the new interface on this version.  I updated to the latest and it still does not work.

What I had to do was use the legacy interface.  The bug was not related to that interface.  To get to it:

  • Login to FreeNAS and click the gear in the upper right corner
  • Click Legacy Web Interface