Enable Thick Provisioning for Nova

Problem

• By default in Platform9 Managed OpenStack, instances ephemeral disks are thin-provisioned, meaning that no disk space is allocated upfront.
• For performance reasons, one may want to preallocate this disk on the underlying filesystem or otherwise use "thick" provisioning.

Environment

• Platform9 Managed OpenStack - All Versions
• Nova

Procedure

1. Set the following on each compute host where thick provisioning should be enabled.

/opt/pf9/etc/nova/conf.d/nova_override.conf.

[DEFAULT]preallocate_images = space

2. Restart the Compute service.

# service pf9-ostackhost restart

For any newly-created instances, the disk file will now be expanded. Any existing instances will remain to be thin-provisioned.

Additional Information

For more details on this option and why it should be enabled, please refer: OpenStack Docs - Nova - Configuration Options.