Storing docker images on a separate volume

Docker is consuming my boot volume quickly, I wanted to dedicated a hard drive just for docker images.

Provision ext4 volume

1. Start gdisk program (new hard disk: /dev/sdb)
   

   sudo gdisk /dev/sdb

2. Remove all partition from the hard disk

   d delete a partition

3. Create a new partition

   n add a new partition
   Command (? for help): n
   Partition number (1-128, default 1): 
   First sector (34-209715166, default = 2048) or {+-}size{KMGTP}: 
   Last sector (2048-209715166, default = 209715166) or {+-}size{KMGTP}: 
   Current type is 'Linux filesystem'
   Hex code or GUID (L to show codes, Enter = 8300): 
   Changed type of partition to 'Linux filesystem'
   

4. Save the partition on disk

   w write table to disk and exit
   Command (? for help): w
   
   Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
   PARTITIONS!!
   
   Do you want to proceed? (Y/N): y
   OK; writing new GUID partition table (GPT) to /dev/sdb.
   The operation has completed successfully.
   admiral@LorientK2:~$ sudo mkfs -t ext4 /dev/sdb1 
   mke2fs 1.42.9 (4-Feb-2014)
   Discarding device blocks: done                            
   Filesystem label=
   OS type: Linux
   Block size=4096 (log=2)
   Fragment size=4096 (log=2)
   Stride=0 blocks, Stripe width=0 blocks
   6553600 inodes, 26214139 blocks
   1310706 blocks (5.00%) reserved for the super user
   First data block=0
   Maximum filesystem blocks=4294967296
   800 block groups
   32768 blocks per group, 32768 fragments per group
   8192 inodes per group
   Superblock backups stored on blocks: 
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
    4096000, 7962624, 11239424, 20480000, 23887872
   
   Allocating group tables: done                            
   Writing inode tables: done                            
   Creating journal (32768 blocks): done
   Writing superblocks and filesystem accounting information: done

5. Create a new ext4 fs on the partition

   sudo mkfs -t ext4 /dev/sdb1

Mounting the new partition on boot

1. Create a mounting point (e.g. /media/data)

   sudo mkdir /media/data

2. Edit /etc/fstab

   sudo vi /etc/fstab

3. Add line to the end of file

   /dev/sdb1       /media/data     ext4    defaults        0       2

4. Reload mount

   sudo mount -a

Bind /var/lib/docker to the new partition

1. Create docker directory in the new partition

   sudo mkdir /media/data/docker

2. Stop docker service

   sudo service docker stop

3. Copy existing docker content to new directory

   sudo rsync -aXS /var/lib/docker/. /media/data/docker/

4. Compare directories

   sudo diff -r /var/lib/docker /media/data/docker

5. Edit /etc/fstab

   sudo vi /etc/fstab

6. Add line to the end of file

   /media/data/docker      /var/lib/docker none    bind    0       0

7. Reload mount

   sudo mount -a

8. Restart Docker

   sudo service docker start

Reference

• Install a new hard drive on Ubuntu documentation
• Moving docker images location to different partition