lvreduce allows you to reduce the size of a logical volume. Be careful when reducing a logical volume's size, because data in the reduced part is lost!!!
You should therefore ensure that any filesystem on the volume is resized
before running lvreduce so that the extents that are to be removed are not in use.
Shrinking snapshot logical volumes (see
lvcreate(8) for information to create snapshots) is supported as well. But to change the number of copies in a mirrored logical volume use
lvconvert (8).
Sizes will be rounded if necessary - for example, the volume size must be an exact number of extents and the size of a striped segment must be a multiple of the number of stripes.