High Availability Series Part 4 - Summary

This article was last updated on: February 7, 2024 pm

  1. Part 1 of a highly available series - Overview - Dongfeng Weiming Technology Blog (e-whisper.com)
  2. High Availability Series Article 2 - Traditional Layered Architecture Technology Solution - Dongfeng Weiming Technology Blog (e-whisper.com)
  3. Article Series No. 3 - NGINX High Availability Implementation - Dongfeng Weiming Technology Blog (e-whisper.com)

VI Summary

High Availability HA (High Availability) is one of the factors that must be considered in the design of the system architecture, which usually refers to reducing the time that the system cannot provide services through design.

Methodologically, high availability is throughredundancy+Failoverto achieve.

The recommended high-availability solution of the entire manufacturing system architecture passes through each layerredundancy+FailoverTo synthesize the implementation, specifically:

  1. Client layer arrive Load balancing layerHigh availability is achieved through redundancy of the load balancing layer, and the specific practice is keepalived + NGINX automatic failover
  2. Load balancing layerarrive App service layerHigh availability is achieved through redundancy of the application service layer, and the common practice is the survivability detection and automatic failover between nginx and the application server
  3. App service layerThe high availability to the database “read” is achieved through the redundancy of the read library, the common practice is to perform “master-slave replication, read-write separation” through the database layer, and the database connection pool of the application service layer configures the IPs of multiple read libraries to ensure automatic failover
  4. App service layerThe high availability of database “write” is achieved through redundancy of write libraries, and the specific practice varies according to the type of database.


Appendix 1: Comparison table in English and Chinese

Chinese English English abbreviation Notes
Availability Availability
Downtime Downtime
Mean Time Between Failures (Or Mean Time Between Failures) Meantime between failure MTBF
Average time to repair Mean time to repair MTTR
Failover fail-over
Load balancing load balance
Active-slave switchover (active to standby) Active-passive
Duplex switching Active-active
Redundancy redundant
Browser browser
Client client
Single application monolithic application
Web server Web Server
Polling Round Robin RR
Weighted Cycle Weighted Round Robin WRR

High Availability Series Part 4 - Summary
Posted on
September 28, 2021
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