The situation: We have a 6 disk RAID6 array in our server. We forgot to keep a bigger space for the root partition and used up all remaining space. Now, if we extent the array with +1 disk and reconfigure the array, we can see that the sda have got an increased size compared to the previous data with lsblk, but I have no idea how to extend the root partition now. Anyone can tell me how can I do that?
When you see bigger space in your disk you can create new partition there, add it as additional storage in VG, then extend LV and at the end extend the filesystem for root.