Resizing Cloud Harddrive

Question

I recently upgraded the harddrive from 20GB to 50Gb using the web interface of my cloud service.

But df -h:

  Filesystem      Size  Used Avail Use% Mounted on
  /dev/vda1        20G   19G   47M 100% /
  udev            488M  4.0K  488M   1% /dev
  tmpfs           200M  264K  199M   1% /run
  none            5.0M     0  5.0M   0% /run/lock
  none            498M     0  498M   0% /run/shm
  none            100M     0  100M   0% /run/user

Clearly not a 50 GB partition.

fdisk -l gives:

Disk /dev/vda: 53.7 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 cylinders, total 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
Disk identifier: 0x00064eed

 Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048    41940991    20969472   83  Linux

Disk /dev/sda: 53.7 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 cylinders, total 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
Disk identifier: 0x00064eed

Device Boot Start End Blocks Id System /dev/sda1 * 2048 41940991 20969472 83 Linux

How do i proceed from here to make the partition a 50GB without loosing data.

OS is Ubuntu 12.10.

Update and "solution" After some help from the accepted solution i created mounted a new partition in the remaining 30GB free space and mounted it as my biggest subdirectory, /var:

Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1        20G  7.7G   12G  42% /
udev            487M  4.0K  487M   1% /dev
tmpfs           200M  268K  199M   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            498M     0  498M   0% /run/shm
none            100M     0  100M   0% /run/user
/dev/vda2        30G   13G   17G  43% /var

Answer 1

If there's only one partition, do this:

• fdisk /dev/<drive>
  • p - observe current partitions.
  • d - delete entire the partition.
  • n - make new primary partition #1. Make sure it spans the whole disk (I've been able to just accept all the defaults)
  • a - make that partition bootable again.
  • p - make sure it looks like the output of the first print.
  • If needed, use t to change the partition type to match first print.
  • If everything looks right, w to write changes.
• resize2fs /dev/<drive>1.

These steps have worked for me every time for VMs on my XenServer cluster.

As always, if there's any really important data, make sure you have a recent backup.

Answer 2

If you are running an ubuntu-cloud image, it should have the cloud-init package installed by default, which should take care of this for you automatically.