How To: Extend (Make it bigger) an ext3 formatted LVM partition
1. Extend the LV partition
lvextend –L +1GB /dev/vgroot/lvsrv
2. Adjust the filesystem (ext3) to the new size of the partition
ext2online /dev/vgroot/lvsrv
3. Occasionally you can tell the command ext2online how big the filesystem should be, the command above usually resizes the filesystem to use the full amount of the partition
ext2online /dev/vgroot/lvsrv 5G
Update February 2nd, 2012
The above steps were written a long time ago (I think in 2008) and on a SLES9 machine.resize2fs /dev/vgroot/lvsrv