DR is Disaster Recovery, and Standby is the server side of a DR process.

Hot Standby, specifically, is a method of redundancy in which system A runs simultaneously alongside system B. If system A fails, system B kicks in immediately. As the systems run in sync, there is no real downtime suffered – the only delay is the length of time it takes for the DNS changes to be made. This is like getting a SIM moved to a new supplier; as the networks/DNS servers around the world catch up to the changes, your users will automatically be directed to your new system.

In (very) simple terms, it’s easiest to think of Standby as the process of transferring the contents of one box to another, with each Standby type having specific latency parameters attached. This is important, as latency is the speed at which data transfers from point A to point B in a network. In terms of your e-Learn Design services, point A is your original server, and point B is the new server to which your data is transferred in the event of a DR occurrence.

Cold Standby

Daily backup

Your data is safe, but there is no immediately available ‘box’ to transfer it to. Latency includes the time it takes to build and configure your new ‘box’, and only then can the transfer of data begin.

Warm Standby

As standard

Backups are taken and there is a pre-configured ‘box’ available, ready should it ever be needed. Latency depends on the amount of data you need to have transferred. Small = fast; large = slow.

Hot Standby

Optional

Both ‘boxes’ of data are kept in sync at all times, which makes latency exceptionally fast. To get back up and running, all you need are DNS changes to redirect the URL from server A to server B.