High availability is a system design approach and associated service implementation that ensures a prearranged level of operational performance will be met during a contractual measurement period.
Users want their systems, for example hospitals, production computers, and the electrical grid to be ready to serve them at all times. Availability refers to the ability of the user community to obtain a service or good, access the system, whether to submit new work, update or alter existing work, or collect the results of previous work. If a user cannot access the system, it is said to be unavailable. Generally, the term downtime is used to refer to periods when a system is unavailable.
Active / Active
A key to an effective, resilient and robust network is a good design. Big IP design is a key for faster and more effective failover leading to greater availability and lesser convergence time. This blog is written with the deployment considerations that are done.
A Big IP works like a switch, having VLAN’s and Spanning Tree Protocol. This enables the Big IP to fit right into your LAN design. You are offered with choices of Active/Standby (Failover) pair or Active/Active or as I like to call it, the “load balance your load balancer” pair, which doubles up on covering for each other. All this is feasible with the concept of “Floating IP”, “Gratuitous ARP” or “Mac Masquerading”.