Backup Virtual Server Connection Persistence in Load Balancing
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Solution Overview
Problem
In load balancing systems, when a primary virtual server fails, the backup virtual server takes over but returning traffic to the primary server after it becomes available can overwhelm the primary server, leading to performance issues and a suboptimal user experience.
Innovation Solution
Implement a method where the backup virtual server maintains existing connections and requests, allowing the primary server to gradually resume new connections, thereby preventing network traffic surges that could overwhelm the primary server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backup virtual server takes over all traffic from the failed primary virtual server, then service continuity is maintained, but the primary server may be overwhelmed when it becomes available again
Solution Approach 1:
The patent applies partial action by having the backup virtual server maintain only a subset of connections (those established during its backup period) rather than taking over all traffic. This prevents the primary server from being overwhelmed when it becomes available, while still ensuring service continuity for connections that the backup server actively managed.
Solution Approach 2:
The patent segments the traffic management by distinguishing between connections established by the primary server and those established by the backup server. The intermediary device tracks connection origins and directs traffic accordingly, separating the handling of different connection types to prevent overload on the recovering primary server.
2Productivity
If the primary virtual server immediately resumes handling all traffic after becoming available, then full service capacity is restored, but the server may experience performance degradation due to sudden load
Solution Approach 1:
The patent implements preliminary action by having the intermediary device prepare traffic routing in advance based on connection tracking data. When the primary server becomes available, traffic is gradually redirected based on pre-established connection information, preventing sudden load spikes and allowing the server to recover smoothly while maintaining full service capacity.
3Reliability
If the backup virtual server maintains all connections during primary server failure, then connection persistence is ensured, but the primary server cannot efficiently regain traffic upon recovery
Solution Approach 1:
The patent uses feedback mechanisms where the intermediary device continuously monitors server availability status and connection states. Based on this feedback, it dynamically adjusts traffic routing decisions, directing new connections to the primary server when available while maintaining persistence for existing connections through the backup server, thus optimizing both reliability and recovery efficiency.
Data Source
AI summary
The present disclosure presents systems and methods for maintaining persistence of a backup virtual server on connections currently serviced by the backup virtual server. A virtual server operating on an intermediary network device and identified as a primary virtual server for a first connection may receive a request via the first connection. The intermediary device may forward the first request to a backup virtual server of the virtual server in response to identifying that the virtual server is unavailable. The intermediary device may later identify that the virtual server is available. The virtual server may establish a new connection responsive to receiving a connection request while the intermediary device may forward a second request received via the first connection to the backup virtual server instead of the virtual server responsive to identifying that the virtual server is configured not to preempt the backup virtual server from maintaining connections currently maintained by the backup virtual server.