The vast array of services and pricing structures available in the cloud provide enterprises with unprecedented scope for cost savings. They offer the elasticity to scale your IT infrastructure to match your workload and performance requirements. And they allow you to pick and choose services and costing options that best suit the nature of your IT environment—whether it be development and testing, an ecommerce website or occasional big data analysis.
But being spoilt for choice also has a downside. With such a rich variety of services and features, your cloud bills can quickly become a complex, tangled web of charges. Unnecessary and avoidable costs can go unnoticed. And, without proper understanding of your usage and spending, your monthly cloud bills can be far higher than they need be.
In this post, we identify four such charges on market-leading cloud platform Amazon Web Services. These are costs that lurk deep in your monthly AWS bills, which often go unchecked without proper monitoring and good cloud management practice.
1. Orphan Snapshots
When you terminate an EC2 instance, all attached EBS volumes are deleted by default. But it’s very easy to forget that your snapshots remain on S3 and continue to rack up monthly charges.
Those charges may also be more than you think. Although backups are incremental, the initial snapshot is of the entire volume. What’s more, regular subsequent snapshots over a long retention period may require as much capacity as the initial snapshot. So, even though S3 is cheaper than general purpose SSD, the monthly cost savings of deleting orphan snapshots can be as much as those made by deleting the original EBS volume that was associated with them.
In other words, unless you want to keep orphaned snapshots for creating future EBS volumes, you should delete them as part of your cloud housekeeping. This process is far easier if each volume is tagged when it’s created—with basic metadata about who created it and what it was used for.
2. Data Transfer Costs
In most cases, data transfer into EC2 is free. But transfer out is another matter. This is something that catches many new AWS customers unaware. These costs can quickly mount up and take up a significant chunk of your monthly cloud bill. So it’s important to understand the charges and know how to keep them to a minimum.
The most significant outward charge is from EC2 to the Internet. After an allowance of 1GB per month, you’ll pay up to $0.90 per GB to transfer out of any US Region. In some circumstances, you have to pay for data transfer to other AWS services. And you also pay to move data between AWS Regions.
Rehosted applications are at greater risk of incurring high data transfer charges. This is because they’re not configured to take full advantage of products and features available in AWS. By contrast, rearchitected applications can make use of services, such as CloudFront, to ensure data follows the least expensive route.
And hybrid clouds may also rack up high data transfer charges. For example, an ecommerce website hosted in the cloud may be designed to communicate with an on-premise inventory system. This can be a costly mistake. So it’s important to consider data transfer charges when making incremental migrations to the cloud.
3. Unused Elastic IP Addresses (EIPs)
With each running instance on AWS you get one free Elastic IP address (EIP). However, EIPs are a limited resource. So, to encourage efficient use of addresses, Amazon levies a small hourly charge on EIPs associated with a stopped instance or unattached network interface. To avoid unnecessary costs, you should put measures in place to release EIPs whenever instances are stopped with no immediate plans to restart them.
4. Underutilized Reserved Instances
Reserved Instances, prebooked discounted capacity for a period of 1 or 3 years, can work out significantly cheaper than using standard pay-as-you-go resources. But, even if you make sufficient use of them to make the investment worthwhile, your organization may still end up with idle reservations that could be recycled and put to good use elsewhere.
You could reassign them to completely new IT projects. Or you could repurpose them to handle existing workloads, which may be using more expensive on-demand instances elsewhere in your cloud. If reuse isn’t an option, you could even consider selling your unused RIs on AWS Marketplace.
Take Control of Your Costs
Virtually any type of cloud usage can accumulate unnecessary charges without full visibility across your range of enterprise deployments. In a complex cloud infrastructure, even simple mistakes, such as failing to match instance size with workload or preventing cloud sprawl, can be difficult to avoid.
This is why continual monitoring is so important to successful cloud implementation. That way, you’ll take control of your costs, wherever they lurk in your monthly cloud bill, and take full advantage of the different pricing structures, features and services available.
If you like this, you might also like:
How to Estimate Your Cloud Data Transfer Costs
How to Make the Most of Your Unused Reserved Instances