Explanation
When a Compute instance is terminated in OCI, the associated boot volume is not deleted by default. If the termination settings don't explicitly delete the boot volume, it persists and continues to generate storage charges. Because boot volumes are managed under the Block Volumes service, not within the Compute UI, they're easy to overlook-especially in environments with frequent provisioning and teardown. Over time, these orphaned boot volumes can accumulate and contribute to unnecessary costs.
Relevant Billing Model
OCI charges for provisioned block volume storage per GB per month, regardless of whether the volume is actively attached to a compute instance. This applies equally to boot volumes and data volumes. Detached boot volumes incur charges unless explicitly deleted.
Detection
- Lifecycle state is "AVAILABLE"
- No attached instance (attached-instance-id is null or missing)
Remediation
- Delete unattached boot volumes that are no longer needed
- Establish lifecycle policies or instance termination settings that automatically delete boot volumes unless explicitly retained
- Periodically audit the Block Volumes service for orphaned resources