Troubleshoot VMware ESXi VMFS datastore capacity problems caused by snapshots, thin provisioning, logs, ISOs and virtual disk growth.
Start with Check datastore capacity and work through the six diagnostic checks in order.
Record results before changing configuration and validate the original symptom after each controlled change.
Quick checks
Start with the basic checks in this runbook before moving to deeper troubleshooting.
- Confirm the affected service or component is available.
- Check recent configuration or connectivity changes.
- Run the relevant commands and compare the result with the expected state.
Check datastore capacity
Confirm the datastore free-space level and identify VMs or operations affected by the capacity condition.
Identify large files
Review VM directories for large snapshots, virtual disks, logs, ISO files and other known data sources.
Check snapshots
Check for snapshot growth and consolidation warnings before removing or consolidating snapshots.
Check thin provisioning
Compare provisioned and consumed capacity to identify thin-provisioned virtual disks that have grown unexpectedly.
Recover capacity safely
Recover capacity using supported vSphere workflows and remove only confirmed-unused data.
Verify VM health
Verify VM power operations, migrations, snapshots and datastore alarms after capacity is restored.
Useful commands
Run these checks from an appropriate administrative session and replace example values with your environment.
Datastore usage
esxcli storage filesystem listFind large files
du -h /vmfs/volumes/<datastore>/* | sort -hQuick troubleshooting path
Use this sequence to isolate the failing dependency before changing production configuration.
- Check datastore capacity → Confirm the datastore free-space level and identify VMs or operations affected by the capacity condition.
- Identify large files → Review VM directories for large snapshots, virtual disks, logs, ISO files and other known data sources.
- Check snapshots → Check for snapshot growth and consolidation warnings before removing or consolidating snapshots.
- Check thin provisioning → Compare provisioned and consumed capacity to identify thin-provisioned virtual disks that have grown unexpectedly.
- Recover capacity safely → Recover capacity using supported vSphere workflows and remove only confirmed-unused data.
- Verify VM health → Verify VM power operations, migrations, snapshots and datastore alarms after capacity is restored.
What good troubleshooting looks like
Good infrastructure troubleshooting is evidence-driven. Capture the original state, test the dependency that can prove or disprove your hypothesis, make the smallest safe change and repeat the original test.
Symptom → hypothesis → direct test → result → controlled change → validation → documentation