Storage Class Operations

Red Hat

Audience
Public
Technology Integrations
Linux
Source Type
Documentation

Storage classes define how OpenShift and Portworx present storage behavior to workloads. In a FlashArray-backed environment, they are the main abstraction that determines performance, availability, replication behavior, snapshot handling, and backend placement. For virtualization administrators, they are the closest equivalent to combining a datastore selection with a storage policy.

Creating Storage Classes for Specific Use Cases

Storage classes should be designed around workload intent, not just around available storage capacity. A VM boot disk, a latency-sensitive database volume, a general-purpose application PVC, and a replicated DR-backed workload should not all be treated the same if the backend supports better policy alignment.

This task is used to:

  • create repeatable storage policies for common workload types

  • simplify workload placement for administrators and application teams

  • standardize protection and performance expectations

Designing StorageClasses

Workload Category Storage Class Consideration
VM boot disks Consistent provisioning performance, predictable sizing, reclaim governance
VM data disks Throughput and IOPS alignment, snapshot scheduling, expansion support
General-purpose application PVCs Broad compatibility, safe defaults, manageable cost profile
High-availability workloads Synchronous replication consideration, ActiveCluster candidate
DR-oriented workloads Near-zero RPO, ActiveDR candidate, failover validation requirement
Snapshot-heavy workloads Snapshot scheduling and retention integration, clone efficiency
Performance-sensitive workloads Low-latency profile, backend array targeting, QoS consideration

ActiveCluster Storage Class

An ActiveCluster-backed storage class is intended for workloads that require zero RPO across sites or arrays using synchronous replication. This class should be reserved for workloads whose business requirement justifies the operational overhead and backend design needed for synchronous behavior.

When to use ActiveCluster-backed storage

  • Use this storage class when:

  • the workload requires zero RPO

  • synchronous replication is part of the service objective

  • site-level resilience is required

  • the workload can tolerate the architecture and placement requirements of synchronous protection

ActiveDR Storage Class

An ActiveDR-backed storage class is designed for workloads that need near-zero RPO but do not require synchronous replication semantics. This can be appropriate for many enterprise workloads where very low data loss tolerance is required without the constraints of a full synchronous design.

ActiveDR-backed storage

  • Use this class when:

  • very low RPO is required

  • asynchronous protection is acceptable

  • DR readiness is more important than immediate cross-site active operation

Operational considerations and failover expectations

  • When using ActiveDR-backed storage, confirm:

  • the workload is placed on the intended class

  • administrators understand the difference between near-zero RPO and zero RPO

  • DR procedures are documented

  • periodic failover validation is scheduled

Standard Snapshot Tier Storage Class

A standard snapshot-oriented storage class is useful when point-in-time recovery, clone workflows, and operational rollback are more central to the workload than synchronous or DR replication behavior. This class is often appropriate for:

  • development and test workloads

  • rollback-sensitive application tiers

  • VM templates and golden images

  • workloads that depend heavily on cloning or point-in-time restore.

Targeting Specific Arrays

In some designs, allowing Portworx to place workloads automatically is sufficient. In others, administrators need tighter control over which backend FlashArray serves a workload. This may be driven by locality, performance isolation, regulatory boundaries, replication design, or service-level segmentation.

This task is used to:

  • Direct specific workloads to selected FlashArray backends

  • Separate workload classes by backend policy

  • Align workloads with physical or logical protection domains

  • Reduce unpredictable placement for high-priority services

Placement Strategy Considerations

When targeting specific arrays, define placement rules based on:

  • business criticality

  • site or array locality

  • protection model

  • latency sensitivity

Array targeting should be intentional and documented. It should not rely on tribal knowledge.

PVC Expansion

Expanding a PVC is a common Day 2 task as VM disks and application volumes grow over time. In a policy-driven environment, expansion should be routine, controlled, and validated.

Operational workflow for expanding PVCs

  1. In the OpenShift web console, go to Storage > PersistentVolumeClaims.

  2. Select the namespace containing the PVC.

  3. Open the PVC details page.

  4. Use the edit action to increase the requested size if the storage class supports expansion.

  5. Save the change.

  6. Monitor the PVC until the new size is reflected.

  7. If the PVC backs a VM, verify the guest operating system recognizes the expanded capacity as expected.

Application and filesystem considerations

Storage expansion does not always complete entirely at the infrastructure layer. Some workloads and guest operating systems may also require in-guest or application-aware resize handling. Administrators should validate end-to-end, not just PVC size in the console.

Reclaim Policy Management

Reclaim policy determines what happens to backend storage assets when PVCs are deleted. This is one of the most important governance controls in a platform that supports both virtual machines and containerized workloads.

Managing Delete versus Retain behavior
Use Delete when: Use Retain when:
  • The volume is disposable

  • Automatic cleanup is desired

  • No recovery requirement exists after deletion

  • The data must be preserved after PVC deletion

  • The workload is sensitive or regulated

  • Administrators may need to recover or inspect the storage asset manually