Blue Coat highly recommends that if you enable load balancing, you also enable host affinity. By default, if you use load balancing, each connection is treated independently. The connection is made to whichever member of the load-balancing group the load-balancing algorithm selects. If host affinity is configured, the system checks host affinity first to see if the request comes from a known client. If this is a first connection, the load-balancing algorithm selects the group member to make the connection. Host affinity records the result of the load balancing and uses it if that client connects again. Host affinity does not make a connection to a host that health checks report is down; instead, if host affinity breaks, the load-balancing algorithm selects a group member that is healthy and re-establishes affinity on that working group member.
Host affinity methods are discussed in the following table.