iIS Process Engine Components

Full Configuration: Failover and Load Balancing Combined

To deal with heavy loads on the engine and overcome the potential bottleneck of a single database service, additional database services can be added to the failover engine configuration, as illustrated in Figure 1-4.

With a heavily loaded engine, large numbers of state changes need to be written to the engine database simultaneously. Database access is likely to be a performance problem. To accommodate large loads, database access is shared among a set of database service components (which may be running on different nodes) using a database service router in the primary engine unit.

Each service is assigned a unique name and allocated a priority (depending, perhaps, on its host node—see “Engine Component Partitioning” on page 85). When the engine unit needs to access the database, the router provides it the highest priority database access service available. If there are a number of services of equal priority available, the router chooses a database service on a round-robin basis, thus sharing the load among all available services.

Figure 1-4Engine Configuration with Both Failover and Load Balancing

 

 

 

iIS Process

Client Applications

Engine

 

 

 

 

 

 

 

 

Primary

Engine

Unit

Router

Governor

Backup

Engine

Unit

Database

Services

Engine

Database

Chapter 1 Introduction: iIS Process Management 35

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Sun Microsystems 3 manual Full Configuration Failover and Load Balancing Combined, IIS Process, Engine