Availability Guide for Application Design

Availability in the Pathway Transaction-Processing
Environment
Availability Guide for Application Design—525637-004
6-2
Availability Concepts Used in Pathway Applications
This section does not discuss the NonStop Tuxedo system. Refer to Section 5,
Increasing the Availability of Tuxedo Applications, for details on this interface. Nor does
it discuss the Subsystem Programmatic Interfaces (SPI) that enhance availability by
supporting instrumentation and command and response interfaces. This information is
provided in Section 8, Instrumenting an Application for Availability.
Availability Concepts Used in Pathway
Applications
The Pathway transaction processing environment makes use of the full range of
availability concepts. All critical application components make use of one or more of
the following:
•
Immediate persistence
If a process is stopped, it is immediately restarted. These processes are typically
under the control of a monitor process. The monitor receives notice from the
operating system of the failure of a process it is responsible for and restarts it.
Figure 6-1. The Pathway Transaction-Processing Environment
RSC
Pathwa
y
/iTS
Guardian
HP NonStop Kernel
TNS/R or TNS/E
Hardware
Front-End
Application
Client
Component of
Transaction
Monitor
Server
Component of
Transaction
Monitor
System
AP
I
TCP
Requester
Pathsend
Requester
Other
Client
Workstation
Client
NonStop SQL/MP
Database
Manager
TCP
NonStop TS/MP and Pathway/
XM
Pathsend I/FServer
Class
Server
VST501.vdd
RSC/MP