Tech/Engineering

4 Things You Should Know About Your AWS Backup Bill

The majority of migrations from on-premises to AWS environments happen too quickly or without enough planning, causing data protection to be an afterthought. Subsequently, customers typically use “AWS Backup,” the most popular data protection tool natively available in AWS.

AWS Backup helps protect EC2, RDS, and other workloads in AWS, which can help recover from accidental deletions or Disaster Recovery. While AWS Backup is simple to use, it has cost inefficiencies when you plan to retain your data for the long term. 

To better understand your AWS Backup bills and how you can save more money, learn about the four key aspects of your AWS Backup costs below.

Navigate to your AWS Bill

First, navigate to your AWS bill by logging into the AWS Management Console, click on your username in the top right corner, and click “Billing Dashboard” (Figure A).

Figure 1: Navigate to your AWS bill

Once you’re on the dashboard, click “Bills” on the left navigation under “Billing.” At the top of the page, you can select the month you want to analyze.

Figure 2: Select the bill you want to view

Now, let’s take a look at the key things that you need to know about your AWS Backup bill.

1. EBS Snapshots

The cost of EBS snapshots can add up over time, however, they’re a critical part of any AWS environment. To understand your EBS snapshot cost, navigate to the “Elastic Cloud Compute” portion of your bill and expand it. Then, expand the region where your EC2/EBS resources and backups are. Lastly, look under the “EBS” section of the bill.

There are two things you look for on this part of the bill: the size of your EBS volumes and the size of the backups themselves.

Figure 3: EBS snapshot portion of the AWS bill

We’re looking for line items that reference “snapshot data stored.” In our example, we have 539.12GB of snapshots taken. In this example, the snapshot size is small and may indicate that this is a relatively new backup policy or that we don’t have a disciplined backup policy in place to protect important workloads. Over time, backup sizes can grow to be between 3x-8x the size of the utilized figure, depending on the retention policies in place. It can get even larger if your retention policies are not set correctly.

Now you should have a good idea of your monthly spend on EBS snapshots.

2. S3 / Glacier Costs

To find your S3 costs on your AWS bill, navigate and expand “Simple Storage Service.” Because S3 isn’t segmented into “provisioned” and “backup,” you would need to know more about how much of it is production data vs. backups. For example, if you’re not using S3 except for backup, you can assume your S3 usage is only for backup. You will essentially add up all your “GB-mo.” (Figure D)

Figure 4: S3 portion of the AWS bill

As demonstrated by Figure 4, this is a very complicated bill with multiple line items. The “TimedStorage-ByteHrs” section will help you decipher your S3 costs. If you’re using S3 Infrequent Access Storage, it will be listed as “TimedStorage-SIA-ByteHrs.” Many customers often try using scripts or third-party backup software to backup their EBS volumes to S3 or S3-IA. After all, S3 is cheaper than EBS snapshots. While true, the cost of moving it there often involves using your own EC2 resources and temporary EBS snapshots that YOU pay for. Oftentimes, the break-even for moving EBS snapshots to S3 is three or more months, which isn’t a cost-effective solution for your daily and weekly backups.

An additional issue with S3 is the use of S3 versioning, which produces full copies of your S3 objects for every small change that occurs. If your application updated anything in your objects, you could easily have multiple complete copies of your data. This immediately negates the cost savings you had by moving backups to S3 in the first place. We often have customers that tried backing up to S3 but ended up saving more by leveraging Druva’s EC2 Backup Solution, which considerably simplifies backups.

3. RDS Snapshots

Next, let’s take a look at Amazon RDS, which can be another critical part of your AWS infrastructure. Your structured data resides in RDS. Similar to EBS, we want to find how much data we have and the size of the backup. RDS has two classes of databases that it manages differently: Aurora and non-Aurora. Aurora bills you on the auto-sizing utilized capacity, versus the entire provisioned capacity. Both Aurora and non-Aurora come with up to 100% of your allocated database capacity in free backups. For example, if you have 100GB of RDS databases, you get 100GB in backups free. You are then billed upwards of $0.095/GB for your backup.

Figure 5: RDS snapshot portion of the AWS bill

Now, let’s determine the size of our RDS backups. For this, we’ll look for all occurrences of “backup storage exceeding free allocation” (Figure 5) in the RDS section of the bill. In our example, we have the total GB of RDS backup storage we have in the U.S. West (Oregon) region. However, there are a couple of things to look out for here. We have multiple regions in our example and we get free backups equivalent to the storage we are consuming on RDS. However, the free backup you get is not combined into one pool. Instead, it’s isolated to each RDS class and region.

4. Transfer Costs

Transfer costs are billed at $0.02/GB. If larger backups are being transferred on a regular basis to another region, the costs can add up fairly quickly. Make sure to take a look at the “Data Transfer” section of your bill.

Figure 6: Transfer cost section of the AWS bill

For example, if you’re backing up 1GB a day at $0.05/GB (average AWS snapshot price) and running a daily backup with a retention period of 30 days, the total cost would be $0.05/GB plus the $0.02/GB transfer. Your total cost per GB/month becomes $0.07/GB, which equates to a 40% transfer “tax”. Alternatively, if you’re retaining your data in another region for longer periods, this transfer tax becomes lower for each additional month you leave your data there.

Meet Druva at AWS re:Invent!

If you’d like to speak to us about how to reduce the costs of your AWS Backup bill, along with how Druva, in collaboration with AWS, reduces your overall risks, come chat with us at Booth #2241 during AWS re:Invent. Stay tuned for a follow up blog post on how to optimize your AWS Backup bill after AWS re:Invent.