In part one I described the AWS EBS snapshot mechanism. In this part I will drill deeper on how to calculate the EBS snapshot cost. I will show how to be able to do a rough estimation or even to perform an accurate cost analysis using monitoring tools.
In order to estimate how large your EBS snapshots will be, you need to know how much your volumes are changing. One way would be to guesstimate,we can use a simple thumb rule that is often used in- backup planning: A typical data volume of a production server changes about 3% a day. Let’s try and calculate the cost. Assuming a 1TB EBS volume, that is 70% full at first. We take snapshots and keep them for 30 days. So, the first full will be taking 700GB (70% of 1TB). For the incremental snapshots we can multiply 30 (days) by 30GB (3% of 1TB) and we reach 900GB. Add them together and we reach about 1.6TB of total snapshot storage. AWS compresses the snapshots when they are stored in S3.