It is common for large organizations using OpenStack to serve thousands of clients or more. Each OpenStack client with its own peculiar needs consumes block storage resources. Deploying Glance (images), Cinder (volumes) and/or Nova (compute) on a single node becomes impossible to manage in large deployments with thousands of clients or more. Scaling OpenStack externally resolves this challenge.
However, it also makes it a practical requirement to virtualize the storage layer with a solution like Red Hat Ceph Storage so you can scale the Red Hat Enterprise Linux OpenStack Platform storage layer from tens of terabytes to petabytes, or even exabytes, of storage. Red Hat Ceph Storage provides this storage virtualization layer with high availability and high performance while running on commodity hardware. While virtualization might seem like it comes with a performance penalty, Ceph stripes block device images as objects across the cluster. This means large Ceph Block Device images have better performance than a standalone disk. Ceph Block devices also support caching, copy-on-write cloning, and copy-on-read cloning for enhanced performance.