The AMI sizes are just enough to accommodate the base system and the most commonly used applications (a few gigabytes in total).
If we simply want to keep our data separated from the system image, or we need more storage, we can create a new EBS volume and attach it to existing instances.
Unfortunately, this is not yet manageable with OpenNebula and thus, we need to use the AWS Management Console or the EC2 Tools.
Find the instance ID and its Availability Zone:
$ ec2-describe-instances INSTANCE i-4e25b229 ami-baba68d3 ec2-23-22-50-12.compute-1.amazonaws.com ip-10-243-61-174.ec2.internal runninggt 0 t1.micro 2012-04-15T13:52:38+0000 us-east-1d aki-825ea7eb monitoring-disabled 23.22.50.12 10.243.61.174 ebs paravirtual xen sg-dc74b3b4 default
Create the new volume (20 GB) inside the same Availability Zone:
$ ec2-create-volume -s 20 -z us-east-1d VOLUME vol-669e3b09 20 us-east-1d creating 2012-04-15T13:57:37+0000
Wait a few seconds for completion and...