986 WebSphere Application Server V8.5 Administration and Configuration Guide for the Full Profile
Session affinity consideration
WebSphere provides session affinity on a best-effort basis. There are narrow windows where
session affinity fails, for example:
When a cluster member is recovering from a crash, a window exists where concurrent
requests for the same session can be received by different cluster members. To avoid or
limit this situation, set the retry timeout to a smaller value, if your environment allows.
A server overload or long processing times can cause requests that belong to the same
session to go to different cluster members.
The session affinity can impact or be impacted by other system configurations, for example:
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