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Sun Java System Calendar Server 6.3 Administration Guide

6.1.4 Choosing a High Availability Model for Your Calendar Server Version 6.3 Deployment

The following table summarizes the advantages and disadvantages of each high availability model. Use this information to help you determine which model is right for your deployment.

Table 6–1 Advantages and Disadvantages of Both High Availability Model

Model 

Advantages 

Disadvantages 

Recommended Users 

Asymmetric 

  • Simple Configuration

  • Backup node is 100 percent reserved

  • Rolling Upgrade, with zero downtime

Machine resources are not fully utilized. 

A small service provider with plans to expand in the future 

Symmetric 

  • Better use of system resources

  • Higher availability

Resource contention on the backup node.  

HA requires fully redundant disks. 

A small corporate deployment that can accept performance penalties in the event of a single server failure 

N+1 

  • Load distribution

  • Easy expansion

Management and configuration complexity. 

A large service provider who requires distribution with no resource constraints