Impact of Data Center Node Failure

When a data center node fails, any user connected to that node who has SU-ed/switched to another user, will either be logged out or return to their original user (when the page is refreshed or a new page is accessed). This is a known issue with data center applications using SU. Once the the user has been re-connected to a running node, they can continue to use SU as normal.

Data Center apps require load balancers that implement session affinity ("sticky sessions"), so that the same cluster node is used for all requests from the same user. That user’s session information is stored locally on the node they are connected to. This means that if that cluster node goes down, the session information is lost. This includes the fact that the user may have SU-ed/switched to another user.

More information can be found here under ‘Session Management’.