Amazon Elastic Block Store (Amazon EBS) provides persistent block level storage volumes that you can use with your EC2 instances. Once you have created a EBS volume it can be attached to an EC2 instance. Once attached, you can create a file system on the EBS volume, run a database on it, or use it in any other way you would use a block device. Amazon EBS volumes are placed in a specific Availability Zone, where it will be automatically replicated to protect you from the failure of a single component.
EC2 Security Groups
To protect your EC2 instances you need to control the inbound and outbound traffic to and from your EC2 instances. Security groups give us the ability to do just that. They act as a virtual firewall that controls the traffic for one or more instances. Upon launching an instance, you associate one or more security groups with the instance. You add rules to each security group that allow traffic to or from the instances the security group is associated to.