What is the downside of enabling 'Sticky Sessions' (Session Affinity) on a Load Balancer?
- A It can lead to 'Hot Spots' where some servers are overloaded while others are idle, and it can cause session loss if a specific backend node fails.
- B It fundamentally breaks the end-to-end TLS encryption required for secure banking and e-commerce transactions on modern browsers.
- C It requires the client to store and transmit a multi-megabyte encrypted cookie with every request, significantly increasing the bandwidth overhead.
- D It prevents the database administrator from adding new servers to the cluster or performing rolling deployments during periods of high user activity.
Sticky sessions (or Session Affinity) ensure that all requests from a specific user are routed to the same physical backend server. This simplifies application design by allowing the server to keep session state in its local memory. However, this creates a 'Hot Spot' risk: if one heavy user performs intensive operations, the server they are 'stuck' to will struggle even if other servers are mostly idle. Furthermore, it complicates high availability; if that specific server crashes, all of its 'stuck' users lose their local session data. A more robust (though complex) alternative is to use a stateless architecture where session data is stored in a distributed cache like Redis.
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