Micha Holzmann wrote:

Now i had to increase the size of partition of sda12 which is a LVM.
I am not sure which is the right way. Within the storage managment
software i can increase the size of the LUN. After rebooting the machine
the additional space is appended at the end of partitions and it is
marked as free. How can i now increase the LVM partition. Which
tool/programm i do need for this task?

The easy way would be to create a new partition to use that free space, then use pvcreate to make it a physical volume and then add it to the volume group. This would mean you'd have two physical volumes on the device belonging to the same volume group.

Michael T. Babcock
http://mikebabcock.ca