Wasted cloud spend from orphaned volumes and snapshots exacerbates the problem of cloud waste. We have previously estimated that $17.6 billion will be wasted this year due to idle and oversized resources in public cloud. Today we’re going to dive into so-called orphaned resources.
A resource can become “orphaned” when it is detached from the infrastructure it was created to support, such as a volume detached from an instance or a snapshot detached from any volumes. Whether you are aware these remain in your cloud environment or not, they can continue to incur costs, wasting money and driving up your cloud bill.
How Resources Become Detached
One form of orphaned resources comes from storage. Volumes or disks such as Amazon EBS, when created, are attached to an EC2 instance. You can attach multiple volumes to a single instance to add storage space. If an instance is terminated but a volumes attached to it have not, “orphaned volumes” have been created. Note that by default, the boot disk attached to every instance is designed to terminate when the instance is terminated (although it is possible to deselect this option), but any additional disks that have been attached do not necessarily follow this same behavior.
Snapshots can also become orphaned resources. A snapshot is a point-in-time image of a volume. In the case of Amazon EBS, AWS snapshots are stored in Amazon S3. EBS snapshots are incremental, meaning, only the blocks on the device that have changed after your most recent snapshot are saved. If the associated instance and volume is deleted, a snapshot could be considered orphaned.
Are All Detached Resources Unnecessary?
Just because a resource is detached it does not mean it should be deleted. For example, you may want to keep:
- The most recent snapshots backing up a volume
- Machine images used to create other machines
- Snapshots used to inexpensively store the state of a machine you intend to use later, rather than keeping a volume around
However, like the brownish substance in the tupperware in the back of your freezer, anything you want to keep needs to be clearly labeled in order to be useful. By default, snapshots and volumes do not always get automatically tagged with enough information to know what they actually are. In ParkMyCloud we see exabytes of untagged storage in our customers’ environments, with no way of knowing if it is safe to delete. In the AWS console, metadata is not cleanly propagated from the parent instance, and you have to go out of your way to tag snapshots before the parent instances are terminated. Once the parent instance is terminated, it can be impossible to identify the source of an orphaned volume or snapshot without actually re-attaching it to a running instance and looking at the data. Tag early and tag often!
The Size of Wasted Spend
To estimate the size of the problem of orphaned volumes and snapshots, we’ll start with some data from ParkMyCloud customers in aggregate. ParkMyCloud customers spend approximately 15% of their bills on storage. We found that 35% of that storage spend was on unattached volumes and snapshots. As detailed above, while this doesn’t mean that all of that is wasted, the lack of tagging and excess of snapshots of individual volumes indicates that much of it is.
Overall, an average of 5.25% of our customers’ bills is being spent on unattached volumes and snapshots. Then applied to the $50 billion estimated to be spent on Infrastructure as a Service (IaaS) this year gives us a maximum of up to $2.6 billion wasted this year on orphaned volumes and snapshots. This is a huge problem.
Based on the size of this waste and customer demand, ParkMyCloud is developing capabilities to add orphaned volume and snapshot management to our cost control platform.
Interested? Let us know here and we’ll notify you when this capability is released.