pvdisplay

vgdisplay

lvdisplay

resize logical volume

lvextend -l +100%FREE <path to lv e.g.dev/fsilun/lvfsilun>

File descriptor 7 (pipe:[13154434]) leaked on lvextend invocation. Parent PID 3865: bash
  Size of logical volume fsilun/lvfsilun changed from 250.00 GiB (64000 extents) to 1000.00 GiB (256000 extents).
  Logical volume lvfsilun successfully resized

and than resize filesystem

resize2fs -p /dev/mapper/fsilun

resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/fsilun/lvfsilun is mounted on /mnt/fsi; on-line resizing required
old desc_blocks = 16, new_desc_blocks = 63
Performing an on-line resize of /dev/fsilun/lvfsilun to 262144000 (4k) blocks.
The filesystem on /dev/fsilun/lvfsilun is now 262144000 blocks long.