Hello, I saw that kolla-ansible had allow cinder coordination backend to be configured. And it can be set to "redis" or "etcd" in /etc/kolla/gloabls.yml [1]. Based on my current understanding, this option enables cinder-volume active/active. 1. I would like to ask, between Redis and Etcd, which one is more recommended or what are their pros and cons? 2. And I have saw the spec of cinder-volume a/a[2]. Is it sufficient to configure [coordination]backend_url and [DEFAULT]cluster to use Cinder volume active/active, or are there any other considerations? Could any reference for Cinder volume active/active configuration and usage documentation be recommended ? I would appreciate for any help. Best wishes. Han Guangyu [1] https://github.com/openstack/kolla-ansible/blob/master/etc/kolla/globals.yml#L539 [2] https://specs.openstack.org/openstack/cinder-specs/specs/ocata/ha-aa-job-distribution.html