vRealize Orchestrator supports both scale-up and scale-out scalability. 

Scale Up

A vRealize Orchestrator instance supports up to 300 concurrent workflow instances in the running state. Workflow instances that are in the waiting or waiting-event states do not count toward that number. You can design long running workflows that preserve resources by using the wait elements of the workflow palette.

A vRealize Orchestrator instance supports up to 35,000 managed virtual machines in its inventory. You can increase the memory and vCPU of the vRealize Automation appliance virtual machines to enable the scaling up of vRealize Orchestrator. For more information on increasing the memory allocated for the embedded vRealize Orchestrator to take advantage of the scaled up vRealize Automation appliance, see VMware Knowledge Base article 2147109.

Scale Out

In the current design, you can scale out vRealize Orchestrator using a cluster of vRealize appliances that have the embedded vRealize Orchestrator appropriately configured using the same settings. By using a vRealize Orchestrator cluster, you can increase the number of concurrent running workflows, but not the number of managed inventory objects. When clustering a vRealize Orchestrator server, choose the following cluster type:

  • An active-active cluster with up to five active nodes. Use a maximum of three active nodes in this configuration.

In a clustered vRealize Orchestrator environment you cannot change workflows while other vRealize Orchestrator instances are running. Stop all other vRealize Orchestrator instances before you connect the vRealize Orchestrator client and change or develop a new workflow.

Table 1. Design Decisions on vRealize Orchestrator Scale-Out

Decision ID

Design Decision

Design Justification

Design Implication


Configure vRealize Orchestrator in an active-active cluster configuration.

Active-active clusters allow both vRealize Orchestrator servers to equally balance workflow execution.

When you cluster the vRealize Automation appliances, the vRealize Orchestrator instances embedded within them are automatically clustered.