I'll be meeting up with the Asian retailer somewhere in the city this coming Thursday, to discuss the High Availability solution I've designed for the company.

In the HA solution I've designed, I proposed a two-node cluster. A cluster is a group of computers performing together to provide a service. Each computer in the cluster is called a node. There are 2 kind of configurations for a cluster. One's a Active/Passive, and the other's a Active/Active. In an Active/Passive configuration, which is valid only for 2-node clusters, only one node will service all incoming requests. When that node fails, the other node takes over. In an Active/Active configuration, all nodes service all requests, and when one node fails, the other nodes take over all requests.

How does a cluster detect when a node has failed? This is achieved by having a network heartbeat. A node is considered alive (has a heartbeat), when it responds to a "Hello, are you alive?" message. If it doesn't respond within a specific timeframe, then it is considered dead.

My service charges for implementing the HA solution over (estimated) 3 days is at $3000, which is pretty cheap. If it lasts more than 3 days, I don't get paid more. If it takes less than 3 days, I'll be glad. This is not inclusive of the hardware and software costs, at $151,378. Needless to say, I believe the Asian retailer to be capable of getting their Return On Investment (ROI) on this investment very rapidly.

By April this year, I'll be able to sign up as a Government Supplier at GeBiz (as PM Lee had announced in the Parliament which I visited recently and blogged about ) and provide my professional IT services, which includes software development, systems maintenance, systems integration, and other IT solutions.