> man pvremovePVREMOVE(8)            System Manager's Manual           PVREMOVE(8)NAME       pvremove  remove a physical volumeSYNOPSIS       pvremove    [--commandprofile    ProfileName]    [-d|--debug]       [-h|--help]    [-t|--test]     [-v|--verbose]     [--version]       [-f[f]|--force   [--force]]   [--reportformat   {basic|json}]       [-y|--yes] PhysicalVolume [PhysicalVolume...]DESCRIPTION       pvremove wipes the label on a device  so  that  LVM  will  no       longer recognise it as a physical volume.OPTIONS       See lvm(8) for common options.       -ff, --force --force          Force the removal of a physical volume belonging to an          existing volume group.  Normally vgreduce(8) should be          used  instead  of  this  command.  You cannot remove a          physical volume which in use by  some  active  logical          volume.       -y, --yes          Answer yes to all questions.SEE ALSO       lvm(8), pvcreate(8), pvdisplay(8), vgreduce(8)Sistina SoftwaLVMUTOOLS 2.02.166(2)-RHEL7 (2016-09-28)   PVREMOVE(8)Q: Why the two fs? 
Why does pvremove have a duplicate force in the man page?
linux;rhel;lvm
It's a safety switch, kind of like the --please-destroy-my-drive option in hdparm. By default the program will refuse to do such a thing (as it will likely result in something broken) but it has an option to override, for people who really really really know what they are doing (at least, in their imagination).Explanation as provided by the program itself (in addition to the manpage you already quoted)# pvremove /dev/loop0  PV /dev/loop0 is used by VG foobar so please use vgreduce first.  (If you are certain you need pvremove, then confirm by using --force twice.)# pvremove --force /dev/loop0  PV /dev/loop0 is used by VG foobar so please use vgreduce first.  (If you are certain you need pvremove, then confirm by using --force twice.)# pvremove --force --force /dev/loop0  WARNING: PV /dev/loop0 is used by VG foobarReally WIPE LABELS from physical volume     /dev/loop0 of volume group foobar [y/n]? y  WARNING: Wiping physical volume label from /dev/loop0 of volume group foobar  Labels on physical volume /dev/loop0 successfully wiped.It really doesn't want to do it and even asks for confirmation after using -ff (if ran in interactive mode).As to why --force twice, wouldn't once be enough? LVM uses --force in other places for slightly less critical actions, so it's probably to catch people who are already in the habit of using a single --force with other LVM commands.