Unable to Extend a Volume

Problem

• Extending a volume results in error: "Failed to schedule_extend_volume: No valid backend was found."
• The host does not have sufficient space for thin provisioning. The ratio of provisioned capacity over total capacity 1.47 has exceeded the maximum oversubscription ratio 1.00 on host

Environment

• Platform9 Managed OpenStack - All Versions

Cause

• Nova-Scheduler log shows "No valid backend was found" error.

• On the host, we can see that the max_over_subscription_ratio is set to "1" in / opt/pf9/etc/pf9-cindervolume-base/conf.d.

Resolution

1. The host does not have sufficient space to extend the volume. Add additional capacity to further extend the volume.

Additional Information

OpenStack documentation for more information relating to oversubscription for thinly-provisioned volumes.