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How to extend the volume (Linux)?

It is possible to extend the Volume from Horizon dashboard.

Another method is to create a new volume, attach it to the VM, copy all the data from the old volume to the new one, check if the data is properly copied, then detach and delete the old one. Not all filesystems are resizable.

 

1. It is strongly recommended to backup the volume by creating Volume Snapshot before proceeding with extending the volume.
2. If you have a volume < 2TB and you want to extend it above 2TB, please do not follow below instructions. Instead please create a new volume, format it according to another article: HOW TO ATTACH A VOLUME TO VM (>2TB) ON LINUX?, attach it to the VM, copy the data from the old volume to the new one, check if it is fully copied, detach and delete the old volume.


You may use following guide to backup the volume:

 How to create volume Snapshot?

 

Resizing the volume:


In this tutorial we will resize 1GB volume to 5GB.

First we need to extend the volume in Horizon.

Lets say that we have 1GB volume attached to our instance as /dev/vdb

 

volume

 

And we have it mounted in our Linux machine as /dev/vdb1

 

# df -kh
Filesystem Size Used Avail Use% Mounted on
udev 478M 0 478M 0% /dev
tmpfs 100M 11M 89M 11% /run
/dev/vda1 7.8G 5.2G 2.3G 70% /
tmpfs 497M 0 497M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 497M 0 497M 0% /sys/fs/cgroup
tmpfs 100M 0 100M 0% /run/user/1001
/dev/vdb1 991M 322M 603M 35% /mnt/vol2


We already have some data on it, we don't want to lose.


First we need to unmount it in Linux:

# umount /dev/vdb1

 

Then detach it in Horizon by clicking "Manage Attachments" > "Detach Volume"

 

Detach Volume

detaching
 

After detaching we will have "Extend Volume" option available.

 

Extend Volume

Extend Volume

We enter new size, for example 5GB and click "Extend Volume"


Extend Volume

Our new volume size is now 5GB.
Attach it to your Virtual Machine again.
Now we need to extend our /dev/vdb partition in Linux.

Expand the modified partition using growpart (and note the unusual syntax of separating the device name from the partition number):

# growpart /dev/vdb 1

 

Next use resize2fs:

# resize2fs /dev/vdb1
resize2fs 1.42.13 (17-May-2015)
Please run 'e2fsck -f /dev/vdb1' first.

 

Most of the time a filesystem check will be recommended by the system.

# e2fsck -f /dev/vdb1
e2fsck 1.42.13 (17-May-2015)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vdb1: 41/65536 files (31.7% non-contiguous), 90414/261888 blocks

 

After doing e2fsck we proceed with extending partition:

# resize2fs /dev/vdb1
resize2fs 1.42.13 (17-May-2015)
Resizing the filesystem on /dev/vdb1 to 1310459 (4k) blocks.
The filesystem on /dev/vdb1 is now 1310459 (4k) blocks long.

 

We can now mount our extended volume again.

# mount /dev/vdb1 /mnt/vol2

 

# df -kh
Filesystem Size Used Avail Use% Mounted on
udev 478M 0 478M 0% /dev
tmpfs 100M 11M 89M 11% /run
/dev/vda1 7.8G 5.2G 2.3G 70% /
tmpfs 497M 0 497M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 497M 0 497M 0% /sys/fs/cgroup
tmpfs 100M 0 100M 0% /run/user/1001
/dev/vdb1 5.0G 322M 4.4G 7% /mnt/vol2

The new size is now 5GB and the data that were previously there are intact.