About an N1 configuration
NOTE: An N+1 DS-System must be licensed for this type of configuration from the DS-License Server. For instructions, see the DS-License Server User Guide.
An N+1 DS-System consists of at least three DS-System nodes on the same LAN working together to provide backup and restore services for DS-Clients. Each DS-System node performs its own storage and retrieval activities, but share a common database and online storage.
The benefits of using an N+1 DS-System include performance, scalability, and redundancy. All the nodes share the backup processing load and if a node fails, the N+1 DS-System continues to function. Hardware can be added to the extensible storage as required.
To ensure the nodes do not run conflicting activities, one node is chosen as random to be the DS-Director. The DS-Director node keeps track of the data storage, sends notifications, and distributes scheduled activities for the entire N+1 DS-System.
NOTE: For N+1 DS-System with 10 or more nodes, the DS-Director is dedicated to DS-Director tasks only.
In the event of a mode failure, the N+1 DS-System will continue running as long as more than half of its nodes are active. This is represented by the formula (n/2)+1. For example:
Total number of nodes | Minimum number of active nodes required to keep system running | Maximum number of inactive nodes |
3 | 2 | 1 |
5 | 3 | 2 |
8 | 5 | 3 |
If the number of active nodes becomes less than the minimum number required to keep the system running, the N+1 DS-System switches to standby mode and waits until enough DS-System nodes start. No DS-System will accept DS-Operator or DS-Client connections.
NOTE: For detailed instructions on how to install and configure an N+1 DS-System, see the Server Software Installation Guide.