Once upon a time, Chris Murphy <lists(a)colorremedies.com> said:
Further I wonder if /etc/lvm/lvm.conf needs
issue_discards = 1
Both / and /home are actually LV's which are made from the LUKS PV. So
trim pass down from dmcrypt to block device isn't enough to do
anything.
LVM passes discards through automatically, assuming the block device
under the PV supports them. The issue_discards option tells LVM to
issue discards itself when PV space is released (e.g. an LV is
removed/reduced).
I'm not sure why issue_discards=1 is not the default, but that's a
separate issue from this change.
--
Chris Adams <linux(a)cmadams.net>