Increase VM Ubuntu Disk Capacity

I'd like to increase the capacity because the ubuntu I'm using in VM is still running out of capacity. Originally, it's 15GB now, so search it and increase the hard disk capacity, and even disk mount? I think I did. But I haven't made any progress since then. It's been coming out at 15GB

I made /dev/sda2 and used /etc/fstab to set the automatic mount It keeps going into emergency mode when booting;; So I annotated that part and it boots well...

Help me...

ubuntu version @-VirtualBox:/$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 16.04.4 LTS Release: 16.04 Codename: xenial

@-VirtualBox:/$ sudo fdisk -l Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x57bc9252

Device Boot Start End Sectors Size Id Type /dev/sda1 2048 31457279 31455232 15G 83 Linux /dev/sda2 31457280 209715199 178257920 85G 8e Linux LVM

Disk /dev/mapper/VolGroup00-test: 50 GiB, 53687091200 bytes, 104857600 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes