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Possible OpenVMS Galaxy Configurations  



An OpenVMS Galaxy computing environment lets customers decide how much cooperation exists between instances in a single computer system.

In a shared-nothing computing model, the instances do not share any resources; operations are isolated from one another (see the Section Shared-Nothing Computing Model).

In a shared-partial computing model, the instances share some resources and cooperate in a limited way (see the Section Shared-Partial Computing Model).

In a shared-everything model, the instances cooperate fully and share all available resources, to the point where the operating system presents a single cohesive entity to the network (see the Section Shared-Everything Computing Model).

Shared-Nothing Computing Model  

In a shared-nothing configuration (shown in Shared-Nothing Computing Model), the instances of OpenVMS are completely independent of each other and are connected through external interconnects, as though they were separate computers.

With Galaxy, all available memory is allocated into private memory for each instance of OpenVMS. Each instance has its own set of CPUs and an appropriate amount of I/O resources assigned to it.  

Figure 3  Shared-Nothing Computing Model  
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Shared-Partial Computing Model  

In a shared-partial configuration (shown in Shared-Partial Computing Model), a portion of system memory is designated as shared memory, which each instance can access. Code and data for each instance are contained in private memory. Data that is shared by applications in several instances is stored in shared memory.

The instances are not clustered.  

Figure 4  Shared-Partial Computing Model  
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Shared-Everything Computing Model  

In a shared-everything configuration (shown in Shared-Everything Computing Model), the instances share memory and are clustered with one another.  

Figure 5  Shared-Everything Computing Model  
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