Live Server Replication with Selective Connection Migration
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Solution Overview
Problem
Existing load balancing technologies struggle to dynamically redistribute resources across hardware and networks due to limitations in connection migration, such as IP address changes causing ongoing connections to terminate and resource shortages at new locations, especially when resources are shared among multiple applications and services with changing loads.
Innovation Solution
A method and apparatus for live replication, where a source server is replicated with a routable IP address, and ongoing connections are selectively migrated to a replica server, allowing for flexible resource management across different networks, preserving live connections and adjusting IP addresses during migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If virtualization technologies (VMotion, Xen's Live Migration) are used to migrate guest OS states, then connection preservation and quality of service are improved, but resource shortage occurs at the new location due to transferring entire traffic
Solution Approach 1:
The patent applies partial action by migrating only selected connections rather than all connections during server migration. The load balancer selectively redirects specific client connections to the replica server while leaving other connections at the source server, thereby preventing resource overload at the destination while still achieving load redistribution and connection preservation for migrated clients.
2Adaptability or versatility
If IP address is changed during migration, then location flexibility is improved, but ongoing connections are terminated and cannot be transferred
Solution Approach 1:
The patent introduces a load balancer as an intermediary between clients and servers. The load balancer maintains connection state information and can redirect connections to either the source or replica server based on current server status. This intermediary enables IP address changes during migration while preserving connection continuity, as the load balancer handles the translation and redirection transparently to clients.
Solution Approach 2:
The patent creates a replica server that copies the state and configuration of the source server, including a copy of the IP address binding. This copying approach allows the system to maintain the original IP address association while having a duplicate server ready to take over connections, thereby enabling location flexibility without breaking existing connections.
3Reliability
If load redistribution is delayed to maintain service quality, then connection stability is improved, but resource utilization decreases
Solution Approach 1:
The patent performs preliminary actions by creating a replica server in advance and pre-establishing load balancing rules before the source server becomes overloaded. The system proactively replicates server state and configures connection redirection pathways ahead of time, enabling rapid load redistribution when needed without causing service disruption or resource underutilization.
Data Source
AI summary
A method and apparatus is disclosed herein for live replication. In one embodiment, the method comprises replicating a source server to create a replica server, assigning a routable Internet Protocol (IP) address to the replica server; and migrating one or more, but not all, on-going connections from the source server to the replica server.