Search Windows Server 2012 Failover Clusters are easier to manage and maintain with the new “Node Drain” and “Resume with Failback” features. This enables nodes to be gracefully drained for planned maintenance. This functionality is part of the infrastructure that enables “Cluster Aware Updating” (CAU) for patching nodes in a cluster. Overview Bringing an individual node down for planned maintenance is a common administrative task, to for example install a Service Pack or hardware upgrades. On a Windows Server 2008 R2 Failover Cluster, this is a manual process where you place a cluster node in PAUSED state, and then move individual Roles (workloads) to the other nodes in the cluster as outlined in this KB article In Windows Server 2012 conducting planned maintenance on Failover Clusters is dramatically simplified, as these steps are automated in the Node Drain (or Node Maintenance Mode) feature. Node Drain Using Node Drain you can automate moving the Roles (workloads) off of a cluster node. Think of Node Drain is to as an enhanced, workload aware Node Pause. Steps automated by Node Drain: 1)      The cluster node is put in a PAUSED state, which prevents other workloads hosted on other nodes from moving to the node. 2)      The Roles (workloads) currently owned by the cluster node, are sorted according to their Priority order. (Priority of Roles is another new Failover Clustering functionality in Windows Server 2012.) 3)      The Roles are then distributed to the other active nodes in the cluster in priority order. Node Drain works with all workloads running on the cluster. For virtual machines, it leverages live migrations and memory-aware intelligent placement. 4)      When all the Roles are moved off of the cluster node, Node Drain operation is completed. Initiating Node Drain through Failover Cluster Manager: Initiating Node Drain through Failover Cluster Manager snap-in is a simple one-click operation: When a node is drained, the cluster will remember the workload(s) that were moved off of the node. When resuming the node after maintenance, you have the option of moving back all the workload(s) to the cluster node.  This will restore the cluster back to the original state it was in before the maintenance. Steps automated Node Resume with Failback: 1)      The cluster node is removed from PAUSED state - this enables workload(s) to move to this node. 2)      The workload(s) that were originally drained from the node are moved back using Failback. Node Drain and Node Resume with Failback will leverage Live Migration for virtual machines so that a node can be drained with no downtime. Live Migration may at times be a long running operation, and there may be scenarios where you wish to quickly drain a node. Node draining provides the flexibility to allow configuration of how VMs should be moved, using either Live Migration or Quick Migration. You also have the granular control to configure the move type to be used based on the priority setting of the VM.  This is configured with the Virtual Machine Resource Type property private property NodeDrainMoveTypeThreshold: Node Drain is a great new time-saving feature in Windows Server 2012 Failover Clustering for conducting planned maintenance. Using this feature, you can easily drain the workload(s) off of a cluster node in a single click, and easily restore them when maintenance operations are completed on the cluster node. Amitabh Tamhane                                                                                                           Lokesh Koppolu Program Manager II                                                                                                        Principal Development Lead Clustering & High Availability                                                                                       Clustering & High Availability Microsoft                                                                                                                          Microsoft