partitioning - Virtualbox out of space

I am getting out of space warnings when I try run and apt-get upgrade.
I am running ubuntu server 14.04 in a virtual machine (virtual box) with a virtual hard drive of 10GB.

It is a very small machine only running bind9 on my local network so strange that it has already run out of space.

If I list the disk space it shows plenty of free space:

df -h

Filesystem                      Size  Used Avail Use% Mounted on
/dev/mapper/ubuntudns--vg-root  8.5G  4.0G  4.2G  49% /
none                            4.0K     0  4.0K   0% /sys/fs/cgroup
udev                            2.3G  4.0K  2.3G   1% /dev
tmpfs                           462M  456K  461M   1% /run
none                            5.0M     0  5.0M   0% /run/lock
none                            2.3G     0  2.3G   0% /run/shm
none                            100M     0  100M   0% /run/user
/dev/sda1                       236M  236M     0 100% /boot

My system uses LVM, which to be honest I don't 100% understand.
This info may help:

sudo vgdisplay
--- Volume group ---
VG Name               ubuntudns-vg
System ID
Format                lvm2
Metadata Areas        1

Metadata Sequence No  3
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                2
Open LV               2
Max PV                0
Cur PV                1
Act PV                1
VG Size               9.76 GiB

PE Size               4.00 MiB
Total PE              2498
Alloc PE / Size       2498 / 9.76 GiB
Free  PE / Size       0 / 0
VG UUID               aax4CX-stxG-jcxV-s2fB-RQxf-43xe-u7Su89


sudo lvdisplay
--- Logical volume ---
LV Path                /dev/ubuntudns-vg/root

LV Name                root
VG Name                ubuntudns-vg
LV UUID                J5OD7h-CdmU-BQ4X-FOIv-0dqu-coeI-y8yvKq
LV Write Access        read/write
LV Creation host, time ubuntudns, 2015-09-17 18:20:27 +0200
LV Status              available
# open                 1
LV Size                8.76 GiB
Current LE             2242
Segments               1

Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           252:0

--- Logical volume ---
LV Path                /dev/ubuntudns-vg/swap_1
LV Name                swap_1
VG Name                ubuntudns-vg
LV UUID                ed2Wcu-u94R-RGYO-pNx7-Dqjt-3dgO-skT9AP

LV Write Access        read/write
LV Creation host, time ubuntudns, 2015-09-17 18:20:27 +0200
LV Status              available
# open                 2
LV Size                1.00 GiB
Current LE             256
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256

Block device           252:1

I have read a number of posts trying to figure this out but really not winning.

Any help would be greatly appreciated :)