| Security | Performance | Throughput | Maintain- ability | Availability | Session | |
|---|---|---|---|---|---|---|
| Single machine | Little isolation between components | Competition for machine resources | Limited to machine resources | Ease of installation and maintenance | Machine is single point of failure | |
| Remote Web server | Allows for firewall/DMZ | - Separation of loads - Performance usually better than local | Independent tuning | - Independent configuration and component replacement
- More administrative overhead - Need copy of plug-in config.xml file | Introduces single point of failure | |
| Separate database server | Firewall can provide isolation | Separation of loads | - Independent tuning - Must consider network bottleneck | - Use already established DBA procedures - Independent configuration - More administrative overhead | - Introduces single point of failure - Use already established HA servers | |
| Separate Web/EJB container | More options for firewalls | Typically slower than single JVM | Clustering can improve throughput | More administrative overhead | Introduces single point of failure | |
| Vertical scaling | Improved throughput on large SMP servers | Limited to resources on a single machine | Easiest to maintain | - Process isolation - Process redundancy | - May use session affinity - Memory-to- memory session replication or persistent session database for session failover | |
| Horizontal scaling | Distribution of load | Distribution of connections | More to install / maintain | Process and hardware redundancy | - May use session affinity - Memory-to- memory session replication or persistent session database required for session failover | |
| Add Web server | Distribution of load | Distribution of connections | - More to install / maintain - Need replication of configs / pages | Best in general | Use load balancer SSL session id affinity when using SSL | |
| One cell | Ease of maintenance | |||||
| Multiple cells | Less lookups and interprocess communication | Harder to maintain than single cell | Process, hardware and software redundancy |
Topology selection considerations
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