RH436 – Red Hat High Availability Clustering — Lesson 3: Shared Storage, iSCSI, Multipathing, LVM, GFS2, and Locking

Learning Objectives

• Explain the structures, services, data, settings, roles, and dependencies governing iSCSI and device mapper multipath.
• Implement and validate clustered LVM, GFS2, and locking using reviewable evidence.
• Evaluate the condition where operators cannot explain the outcome because logs, commands, settings, and acceptance evidence were not captured consistently and select a proportionate corrective response.

Detailed Topics

• iSCSI applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• device mapper multipath applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• clustered LVM applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• GFS2 applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• locking applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.

Instructor Demonstration

The instructor traces an infrastructure team designing a resilient clustered service with controlled failover and shared storage. The walkthrough connects navigation, commands, configuration logic, system messages, and evidence captured in the high-availability cluster build document, failover test evidence, storage design, and recovery runbook. It also tests the exception where operators cannot explain the outcome because logs, commands, settings, and acceptance evidence were not captured consistently.

Hands-On Exercise

Complete a controlled Red Hat exercise covering Shared Storage, iSCSI, Multipathing, LVM, GFS2, and Locking and preserve the verified result in the high-availability cluster build document, failover test evidence, storage design, and recovery runbook.

1. Confirm scope, prerequisites, versions, identities, dependencies, and acceptance criteria.
2. Execute the workflow while recording commands, settings, outputs, events, and system messages.
3. Test normal behavior, one boundary condition, and the stated exception.
4. Document corrections, evidence, ownership, retest criteria, rollback, and handover actions.

Scenario Analysis

• Identify which object, service, policy, setting, or sequence most strongly influences iSCSI.
• Compare two defensible responses and explain technical, security, operational, and support trade-offs.
• Determine how the high-availability cluster build document, failover test evidence, storage design, and recovery runbook should be approved, retained, retested, and updated.

Troubleshooting Guidance

Start where expected behavior first differs from the observed result. Check prerequisites, identity, configuration order, version compatibility, connectivity, status, resource limits, and evidence separately. Treat “operators cannot explain the outcome because logs, commands, settings, and acceptance evidence were not captured consistently” as a hypothesis until commands, logs, settings, and retest outcomes confirm the cause.

Validation Checklist

• Required platform components, identities, permissions, settings, and dependencies are present.
• The high-availability cluster build document, failover test evidence, storage design, and recovery runbook connects each conclusion to objective, reviewable evidence.
• Normal processing, a boundary condition, dependency behavior, and the stated exception were tested.
• Corrections, ownership, retest criteria, rollback, documentation, and operational handover are complete.

Lesson Outcome

Learners can apply Shared Storage, iSCSI, Multipathing, LVM, GFS2, and Locking, explain the resulting platform behavior, and defend the outcome through the high-availability cluster build document, failover test evidence, storage design, and recovery runbook.