I've been reading the lvm faq looking to reduce the size of one of my lvm volumes. Here is what it told me to do:
There is currently no e2fsadm equivalent for LVM 2 and the e2fsadm that ships with LVM 1 does not work with LVM 2.
If you prefer to do this manually you must know the new size of the volume in blocks and use the following commands:
# umount /home
# resize2fs /dev/myvg/homevol 524288
# lvreduce -L-1G /dev/myvg/homevol
# mount /home
My question is: How do I figure out the new size of the volume in blocks? Let's say I want to reduce a volume to 100 gigabytes, what would be the block count?