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Destination address affinity persistence You can optimize your server array with destination address affinity persistence. Destination address affinity persistence, also known as sticky persistence, directs requests for a certain destination IP address to the same server, regardless of which client made the request. This type of persistence provides the most benefits when load balancing caching servers. A caching server intercepts web requests and returns a cached web page if it is available. In order to improve the efficiency of the cache on these servers, it is necessary to send similar requests to the same server repeatedly. You can use the destination address affinity persistence type to cache a given web page on one server instead of on every server in an array. This saves the other servers from having to duplicate the web page in their cache, wasting memory.
Destination Address persistence persists based on the destination address. Any request to the same destination IP will persist to the same member.
Great example is directly from the Session Persistence section of the support site.
Think of an example where LTM is used to balance HTTP sessions for clients across a pool of caching proxies. By directing requests for the same resource (destination) to the same proxy, the efficiency of the cache increases. Destination address affinity ensures that requests to, for example, www.f5.com* always go to the same proxy.