Failover

Redundancy and Failover

Techniques for eliminating single points of failure by duplicating critical components and automatically routing traffic away from failed instances to healthy…

What is Database Replication?

Database replication is the process of continuously copying data from one database server (the primary) to one or more other servers (replicas), so multiple co…

What is a Master-Slave Replication Topology?

A master-slave replication topology has exactly one server (the master) accepting all writes, while one or more slave servers continuously receive and apply a…

What is Transaction Log Shipping and How is it Used?

Transaction log shipping is a high-availability technique where the write-ahead or transaction log records generated on a primary database are continuously cop…

What Is Chaos Engineering for Databases and Why Practice It?

Chaos engineering for databases is the practice of deliberately injecting controlled failures, like killing the primary, introducing replication lag, or partit…

What is HSRP (Hot Standby Router Protocol)?

HSRP (Hot Standby Router Protocol) is a Cisco-proprietary first-hop redundancy protocol that lets two or more routers share a single virtual IP and virtual MAC…

What is VRRP (Virtual Router Redundancy Protocol)?

VRRP (Virtual Router Redundancy Protocol) is an open, IETF-standardized first-hop redundancy protocol — functionally similar to Cisco’s HSRP — that lets a grou…

What is GLBP (Gateway Load Balancing Protocol)?

GLBP (Gateway Load Balancing Protocol) is a Cisco-proprietary first-hop redundancy protocol that, unlike HSRP or VRRP, actively load-balances outbound traffic…

What is Database Replication in System Design?

Database replication is the process of copying data from a primary database to one or more replica databases so the system gains redundancy for fault tolerance…

What is a Single Point of Failure (SPOF)?

A single point of failure (SPOF) is any component in a system whose failure alone causes the entire system, or a critical part of it, to become unavailable, an…

What is a Heartbeat in Distributed Systems?

A heartbeat in distributed systems is a small periodic signal one node sends to another (or to a coordinator) purely to prove it is still alive, and its absenc…

Active-Active vs Active-Passive: What is the Difference?

Active-active means two or more nodes simultaneously serve live traffic and share the load, while active-passive means only one node serves traffic at a time a…