I’ve increased my disk storage. But my storage shows in a different folder in filesystem.
Previously my disk storage was 49 GB. Now increased another 30 GB. Previous 49 GB shows in /dev/vda1 location and new 30GB shows in /dev/sda location. How do I merge this 49GB + 30GB in the same location /dev/vda1

Filesystem      Size  Used Avail Use% Mounted on
udev            984M     0  984M   0% /dev
tmpfs           200M   21M  179M  11% /run
/dev/vda1        49G   49G     0 100% /
tmpfs           997M     0  997M   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           997M     0  997M   0% /sys/fs/cgroup
/dev/vda15      105M  3.6M  101M   4% /boot/efi
/dev/sda         30G  6.1G   23G  22% /mnt/volume_sgp1_01
tmpfs           200M     0  200M   0% /run/user/0