How to Shrink a Logical Volume

Firstly and MOST IMPORTANTLY! We have to UNMOUNT and CHECK FILESYSTEM HEALTH before resizing process:

umount /dev/mapper/{$volumeGroupName}

e2fsck -fy /dev/mapper/{$volumeGroupName}

resize2fs /dev/mapper/{$volumeGroupName} {$newSize}G

Then we have to reduce the logical volume:

lvreduce -L {$newSize}G /dev/mapper/{$volumeGroupName}

And then resize to filesystem with:

resize2fs /dev/mapper/{$volumeGroupName}