Explanation
Why the waste happens and who it affects.
These often accumulate after instance deletion or reconfiguration. Unlike boot volumes, unattached data volumes may be harder to track if not labeled or tagged clearly.
Billing model
The pricing dimensions that drive this cost.
Charged per GB-month of provisioned storage plus volume performance units (VPUs per GB-month; 10 VPUs per GB at the default Balanced level, none at the Lower Cost level), regardless of attachment or usage state.
How to detect
2 checks to find it in your estate.
- Volume lifecycle state is "AVAILABLE" (attached volumes also report AVAILABLE, so state alone is not enough)
- No volume attachment in ATTACHED state references the volume (check with ListVolumeAttachments filtered by volume ID)
How to fix
3 ways to remove the waste.
- Delete unattached block volumes that are no longer needed, taking a backup first if the data may be required later
- Enable Detached Volume Auto-tune so volumes that stay detached are adjusted to the Lower Cost performance level (0 VPUs/GB) after 14 days
- Tag volumes with owner and purpose, and periodically audit the Block Volumes service for orphaned resources
Documentation
Vendor references for pricing and configuration.