Does CA have any tuning guides and how much memory would be the maximum recommended by CA? Ehcache can also be clustered (http://www.ehcache.org/documentation/3.5/clustered-cache.html). Can clustered ehcache be used in Service Catalog?
The ehcache out of the box configuration will be sufficient for almost all configuations. There is no way of implementing ehcache clustering in Service Catalog.