These instructions have been applied to RedHat and CentOS. I have seen some instances, where these instructions broke the VM. (So I make no promises. They worked for me.)
Article: How to Extend LVM Inside a VM
1. Gracefully shutdown virtual machine.
2. SSH into ESX Server as ‘root’ and navigate to the datastore containing the vmdk that you need to extend.
3. vmkfstools -X
4. Start virtual machine and open a terminal window.
5. fdisk /dev/sda (if only 1 disk on linux)
6. in fdisk, create new partition with new freespace (n,new partition#,start,stop)
7. in fdisk, change new partition type to 8e (linux lvm)(t,new partition#,8e)
8. in fdisk print out partition table to verify (p)
9. in fdisk write partition and exit (w)
10. partprobe (shouldn’t be necessary, but rereads partitions)
11. pvcreate /dev/sda3 (if new partition is 3rd partition)
12. vgextend VolumeGroupName /dev/sda3 (add new partition to VG)
13. lvextend -L+1G /dev/VolGroup00/LogVol00 (assuming LogVol00 is lv you wish to grow)
14. ext2online /dev/VolGroup00/LogVol00 (extend an ext3 partition to fill the LV)
(if you want a specific size: ext2online -L10G /dev/VolGroup00/LogVol00)
(if you want to grow a specific size: ext2online -L+1G /dev/VolGroup00/LogVol00)
(Some OSes (CentOS) uses resize2fs: ex. resize2fs /dev/VolGroup00/LogVol00.)