How many process instances can be started?
The number of process instances that can be processed in parallel by the engine is limited to 1000 per Process Governance node by default (Configuration > Process Governance > Infrastructure > Batch processing size). However, depending on the workflow complexity, it can be necessary to reconfigure this number, for example when using
Custom report scripts or local services
High number of parallel branches
Deeply nested branches
Large number of activities per instance
Many task assignments per task (users/user groups)
The process instances have the RUNNING status. If the specified batch processing size is reached, the process instances started additionally have the QUEUED status. You can display them in Instances in 
Process administration. This 
Cross-tenant setting applies to all tenants on this server. To change it, use ARIS Cloud Controller. For further information, refer to the Technical Help of ARIS: Configuration > Command-line tools > ARIS Cloud Controller.
Archive completed process instances regularly to avoid a large number of instances that can have a negative effect on runtime and start times for processes.