Planned and unplanned outage

Planned outage

A planned outage is an interruption to your service that is scheduled in advance. Planned interruptions may be required for maintenance, repairs, or upgrades to a system.

The Red Hat Enterprise Linux High Availability Add-on (Red Hat HA) allows you to manually trigger the movement of workload to another cluster member.

pcs resource move kvm-guest backup-host

Live Guest Relocation (LGR) (z/VM) / Live Migration (KVM):

• z/VM guests cluster:

  • For LGR to work you need a SSI cluster.

• KVM guests cluster:

  • For Live Migration to work you usually need shared storage (or replicated storage), which is mounted read and write between the hypervisors.

• LPARs cluster with KVM guest as workload:

  • Live Migration of the resource is automatically tried when all requirements are met.

Unplanned outage

An unplanned system outage is an interruption to a system or service that was not anticipated, or planned for, in advance. This can be caused by a variety of things, such as power outages, hardware or software failures, network problems, or natural disasters.

Red Hat HA automatically fails over in case of failure as soon as the node has released all Resources (see Fencing/STONITH concept).

LGR (z/VM) / Live Migration (KVM) cannot be used as the guest as you would move a corrupted/broken guest in this case.