// Module included in the following assemblies:
//
// * scalability_and_performance/telco_core_ref_design_specs/telco-core-rds.adoc

:_mod-docs-content-type: REFERENCE
[id="telco-core-openshift-data-foundation_{context}"]
= {rh-storage}

[role="_abstract"]
{rh-storage} is a software-defined storage service for containers that provides block storage, file system storage, and on-premise object storage.

New in this release::

* There are no reference design updates in this release.

Description::
{rh-storage} is a software-defined storage service for containers.
{rh-storage} can be deployed in one of two modes:
* Internal mode, where {rh-storage} software components are deployed as software containers directly on the OpenShift cluster nodes, together with other containerized applications.
* External mode, where {rh-storage} is deployed on a dedicated storage cluster, which is usually a separate Red Hat Ceph Storage cluster running on Red{nbsp}Hat Enterprise Linux.
These storage services are running externally to the application workload cluster.

For telco core clusters, storage support is provided by {rh-storage} storage services running in external mode, for several reasons:

* Separating dependencies between {product-title} and Ceph operations allows for independent {product-title} and {rh-storage} updates.
* Separation of operations functions for the Storage and {product-title} infrastructure layers, is a typical customer requirement for telco core use cases.
* External Red Hat Ceph Storage clusters can be re-used by multiple {product-title} clusters deployed in the same region.

{rh-storage} supports separation of storage traffic using secondary CNI networks.

Limits and requirements::
* In an IPv4/IPv6 dual-stack networking environment, {rh-storage} uses IPv4 addressing.
For more information, see link:https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/latest/html/planning_your_deployment/network-requirements_rhodf#ipv6-support_rhodf[IPv6 support].

Engineering considerations::
* {rh-storage} network traffic should be isolated from other traffic on a dedicated network, for example, by using VLAN isolation.
* Workload requirements must be scoped before attaching multiple {product-title} clusters to an external {rh-storage} cluster to ensure enough throughput, bandwidth, and performance KPIs.

