An active/active system is a network of independent processing nodes, each having access to a common replicated database, such that all nodes can participate in a common application.
In the most general case, the nodes are completely symmetric. Any transaction can be routed within the application network to any node which can read or update any set of data items in the database. This approach provides the most flexibility and maximizes system investment as requests can be load-balanced across all available processing capacity.
Should a node fail, users at the other nodes are unaffected. Furthermore, the users at the failed node can be quickly switched to surviving nodes, thus restoring their services in seconds or less.
An active/active network contains at least two copies of the application database. All database copies are kept in synchronism so that any copy can be used for a transaction. Should a database copy fail, all transactions are routed to a surviving copy.
Providing that the nodes and database copies are geographically distributed, active/active systems provide disaster recovery for little or no cost. Should a disaster take out a node or a database copy, there are others in the network to take their place.
Active/Active Pages:
- Part 1 - What is an Active/Active System?
- Part 2 - Why Does Active/Active Work?
- Part 3 - Shadowbase Database Synchronization
- Part 4 - Eliminate Planned Downtime
- Part 5 - Why Choose Shadowbase Technology?
