In horizontally clustered environment, cluster-enabled application is deployed on multiple physical machines. Each machine is available for requests. Horizontal clusters offers protection over hardware failure, increases efficiency, provides load balancing and process failover. However, since there are many number of physical machines involved the installation and maintenance cost increases proportionally.

In Vertical clustering, multiple application server instances are hosted on the same physical machine. This type of clustering provides increased efficiency, load balancing and process failover. However, if hardware fails then there may not be ready alternative.