Unattached Persistent Disk (GCP)
CostLens finds Compute Engine persistent disks not attached to any instance — billing full provisioned-capacity rates for nothing.
CostLens finds unattached persistent disks flagged by Google's Recommender — disks not attached to any instance while billing full provisioned-capacity rates. These are a common leftover after deleting a VM without deleting its disks.
Deletion is irreversible
Deleting a persistent disk permanently destroys its data. CostLens shows this as an irreversible fix and cannot roll it back. Snapshot the disk first if you might need the data.
How it works
Recommender flags idle disks
Google's Idle Resource Recommender identifies persistent disks with no attachment.
CostLens reads them read-only
Using the recommender.viewer + Compute read scopes from GCP Accounts, CostLens ingests each disk and its projected saving.
What to do
- Confirm the disk is truly orphaned and not a spare kept intentionally.
- If you may need the data, create a snapshot first.
- Delete the disk to stop the charge — via CostLens Apply Fix (irreversible) once write access is granted, or in the Cloud Console.
Severity levels
| Severity | Estimated monthly savings |
|---|---|
| critical | >$500 |
| high | $100–$500 |
| medium | $20–$100 |
| low | <$20 |
Required permissions
- Detect:
roles/recommender.viewer+ Compute read — see GCP Accounts. - Apply Fix (delete): a write role with
compute.disks.delete.
Limitations
- Only disks reported as unattached are flagged; disks backing a stopped instance are left alone.