Hi,

You can serially cluster two WAE devices with the Cisco WAE Inline  Network Adapter installed to provide higher availability in the data  center if a device fails. If the current optimizing device fails, the  inline group shuts down, or the device becomes the overloaded, the  second WAE device in the cluster provides the optimization services.  Deploying WAE devices in a serial inline cluster for scaling or load  balancing is not supported.

More deatils here: Clustering Inline WAEs

Hope this helps.

Regards.

PS: Please mark this as Answered, if this answers your question.