Home > Integrated Products > VxRail > Guides > Planning Guide—VMware Cloud Foundation 5.x on VxRail > Decide whether to join an existing SSO domain
If a Cloud Foundation for VxRail instance is already running in the data center, you can decide if you want this new instance to join the existing SSO domain, or create a new SSO domain. It should be noted that when you join the existing SSO domain, it reduces the number of workload domains the Cloud Foundation on VxRail instance can support. This is due to the limitation of 15 vCenter instances supported in enhanced linked mode. However, if each workload domain is configured with its own SSO, then a maximum of 25 domains is supported.