NonStop Systems Introduction for H-Series RVUs

The Application Server Environment
NonStop Systems Introduction for H-Series RVUs— 540083-001
3-14
Server Handling
application server in use, there might be some restrictions on the reconfigurations that
can be done online).
Effective Use of Multiple Processors
The client/server architecture makes effective use of multiple processors. Figure 3-9
shows how a simple application could be distributed across a three-processor system.
In this figure, three clients are attached to processor 1. Server A also runs in
processor 1. Server B runs in processor 2, and Server C runs in processor 3.
Because any of the servers can run in any processor in the system, all the servers can
service client requests at the same time. This ability of several processors to run
different parts of an application simultaneously in the same system is known as
parallel processing. This feature greatly enhances the performance of applications on
Integrity NonStop servers.
Parallel processing makes it easy for applications to expand. For example, suppose
additional clients are added to the configuration shown in Figure 3-9 on page 3-14,
thus placing a heavy demand on Server A. Capacity planning tools then determine that
processor 3 is the least busy of the three processors. The system administrator can
then configure another copy of Server A in processor 3. The two copies of Server A are
known as a server class.
Figure 3-10 on page 3-15 shows the reconfigured server environment. Note that the
additional client systems are connected to different processors. Application server
components automatically handle the communications paths required for the additional
clients.
Figure 3-9. Parallel Processing
Processor 1
Processor 3
Processor 2
Database
C
Database
B
Server C
Server B
Server A
Database
A
VST024.vsd
Process and link
management
NonStop server
Client A
Client B
Client C