Grow the boot volume of an oracle VM Ubuntu instance

Backup current partition table

sfdisk -d /dev/sdb > sdb_partition_bak.dmp

Execute a dry-run to see the changes that will apply. Install with apt-get install cloud-utils if you don't have it already.

growpart -N /dev/sdb 1

If all looks good:

growpart /dev/sdb 1

Resize file system now:

resize2fs /dev/sdb1

See the change now:

df -h