Persistent storage configuration

To meet workload and scaling needs, you can configure storage services for block, image, object, and file storage. You can configure Red Hat Ceph Storage as a unified back end for all storage services or you can configure alternative back-end storage solutions for these services.

Ephemeral and persistent storage
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RHOSO recognizes two types of storage - ephemeral and persistent:

  • Ephemeral storage is associated with a specific Compute instance. When that instance is terminated, so is the associated ephemeral storage. This type of storage is useful for runtime requirements, such as storing the operating system of an instance.
  • Persistent storage is designed to survive (persist) independent of any running instance. This storage is used for any data that needs to be reused, either by different instances or beyond the life of a specific instance.

RHOSO storage services correspond with the following persistent storage types:

  • Block Storage service (cinder): Volumes
  • Image service (glance): Images
  • Object Storage service (swift): Objects
  • Shared File Systems service (manila): Shares

All persistent storage services store data in a storage back end.

Supported persistent storage solutions
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RHOSO supports the following storage solutions for service back ends:

  • Block Storage service (cinder): Ceph RBD, iSCSI, FC, NVMe-TCP, or NFS back end
  • Image service (glance): Ceph RBD, Block Storage, Object Storage, or NFS back end
  • Object Storage service (swift): PersistentVolumes (PVs) on OpenShift nodes or disks on external data plane nodes
  • Shared File Systems service (manila): CephFS, CephFS-NFS, or alternative back ends such as NetApp or Pure Storage

Red Hat Ceph Storage
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Red Hat Ceph Storage can serve as a unified back end for all RHOSO storage services. The features and functionality of RHOSO services are optimized when you use Red Hat Ceph Storage as the storage back end.

Supported Ceph versions and deployment modes

RHOSO supports external deployments of Red Hat Ceph Storage 7, 8, and 9. You can integrate an external Red Hat Ceph Storage cluster with the Compute service (nova) and one or more RHOSO storage services, or you can create a hyperconverged infrastructure (HCI) environment.

Note

Configuration examples in procedures that reference Red Hat Ceph Storage use Release 7 information. If you are using a later version of Red Hat Ceph Storage, adjust the configuration examples accordingly.
OpenShift Data Foundation integration
You can use Red Hat OpenShift Data Foundation in external mode to integrate with Red Hat Ceph Storage. The use of Red Hat OpenShift Data Foundation in internal mode is not supported.

Storage back end certification
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To promote the use of best practices, Red Hat has a certification process for OpenStack back ends. For improved supportability and interoperability, ensure that your storage back end is certified for RHOSO. Ceph RBD is certified as a back end in all RHOSO releases.