I have a reserved instance on AWS . I want to configure with route 53 failover policy. For this , I want to setup an ondemand passive server, which will takeover , once my primary reserved instance fail. I want to know the charges of this passive server. Will it charge me 24 hours, or only when primary server fails and it takes over. My reserved instance is t2 large
A reserved instance is just like an other Amazon EC2 instance. The reservation is merely a pricing discount and a priority to get capacity when there is high demand.
The concept of a passive server is not used in AWS. If you mean a secondary server that can handle traffic if a primary server fails, then this is a common concept. In fact, rather than running a primary/second server configuration, it is recommended that you run as High Availability within AWS.
A High Availability architecture involves running an application across multiple servers concurrently so that, if one fails, the others can immediately take the load. In contrast to traditional Disaster Recovery scenarios where alternate servers are activated, under a High Availability architecture multiple servers in multiple data centers (Availability Zones) are always handling some of the traffic.
The easiest way to configure this is to use an Elastic Load Balancer across multiple AZs that distributes traffic to Amazon EC2 instances running in multiple AZs.
Instead, if you really only want one server running, you could have another server configured but in a Stopped state. There is no charge for a stopped EC2 instance (but disk storage is still charged). In case the main server fails, you could then Start the other server. Startup time would depend upon the operating system and the software you have configured on the server.