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Compaq Reliable Transaction Router manual 16 Shadow Servers

Models: Reliable Transaction Router

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Figure 1–16 Shadow Servers

RTR Server Types

Figure 1–16 shows a simple shadow conﬁguration. The main (BE) Server at Site 1 and the shadow server (Shadow) at Site

2 both receive every transaction for the data partition they are servicing. Should Site 1 fail, Site 2 continues to operate without interruption. Sites can be geographically remote, for example, available at separate locations in a wide area network (WAN).

Figure 1–16 Shadow Servers

Terminals	Frontends (FE)
	FE

Client

FE

Client

FE

Client

Routers (TR)

TR

Backends (BE)	Database (DB)
BE - SITE 1
Server	DB
BE - SITE 2
Shadow	DB
	DB

ZKO-GS014-99AI

Concurrent server

Note that each shadow server can also have standby servers.

The concurrent server is an additional instance of a server application running on the same node. RTR delivers transactions to a free server from the pool of concurrent servers. If one server fails, the transaction in process is replayed to another server in the concurrent pool. Concurrent servers are designed primarily to increase throughput and can exploit Symmetric Multiprocessing (SMP) systems. Figure 1–17, Concurrent Servers, illustrates the use of concurrent servers sending transactions to the same partition on a backend, the partition A-N.

Concurrent servers allow transactions to be processed in parallel to increase throughput. Concurrent servers deal with the same database partition, and may be implemented as multiple

1–18Introduction

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Compaq Reliable Transaction Router manual 16 Shadow Servers

Contents

Revision/Update Information This is a new manual Reliable Transaction Router Getting StartedJanuary Compaq Computer Corporation Houston, Texas2001 Compaq Computer Corporation This document was prepared using VAX DOCUMENT, VersionUNIX and The Open Group are trademarks of The Open Group Architectural Concepts IntroductionContents 3 Reliability Features 4 RTR Interfaces5 The RTR Environment Glossary Index ExamplesFigures TablesPage Purpose of this Document PrefaceDocument Structure RTR Commands Router InstallationRelated Documentation For all usersReading Path Readers CommentsConventions New termFigure 1 RTR Reading Path System ManagerApplication Programmer If V2 toIntroduction Reliable Transaction RouterRTR Continuous Computing Concepts RTR Terminology Figure 1-1 Client Symbol Figure 1-2 Server Symbol Channel RTR conﬁguration RolesFigure 1-4 Facility Symbol Figure 1-3 Roles SymbolsFE TR Figure 1-5 Components in the RTR Environment Nontransactional messaging Transaction ID Transaction Controller 1-8 IntroductionFigure 1-6 Two-Tier Client/Server Environment Figure 1-7 Three-Tier Client/Server EnvironmentWeb Server Process RTR Client Application Figure 1-8 Browser Applet Conﬁguration1-10 Introduction Figure 1-9 RTR with Browser, Single Node, and Database Figure 1-10 RTR Deployed on Two NodesFigure 1-11 RTR Deployed on Three Nodes 1-12 IntroductionFigure 1-12 Standby Server Conﬁguration Transactional shadowing RTR JournalFigure 1-13 Transactional Shadowing Conﬁguration RTR Server Types Concurrent servers Callout servers Figure 1-15 Standby Servers Transactional shadow serverFigure 1-16 Shadow Servers Figure 1-17 Concurrent Servers User Accounts Facility Figure 1-18 A Callout ServerFigure 1-19 Bank Partitioning Example TR A partition can also have multiple standby servers RTR Networking Capabilities RouterPage Architectural Concepts The Three-Layer ModelFigure 2-1 The Three Layer Model ZKO-GS011-99AIBroadcasts RTR Facilities Bridge the GapFlexibility and Growth Transaction Integrity Flexibility and GrowthThe Partitioned Data Model Object-Oriented ProgrammingFigure 2-2 Partitioned Data Model ZKO-GS012-99AIObjects Table 2-1 Functional and Object-Oriented Programming ComparedMessages Class Relationships Example 2-1 Objects-Deﬁned SamplePolymorphism Object Implementation Beneﬁts XA Support Programmers Reference Manual and the RTR Application Design GuideReliability Features ServersFailover and Recovery Recovery ScenariosRecovery Router FailoverBackend Recovery Router Recovery Frontend Recovery Page RTR Interfaces RTR Management Station RTR Management Station $ RTR RTR SHOW JOURNALRTR CREATE FACILITY DESIGN/ALLROLES=NODEA RTR SHOW FACILITYRTR RTRRECEIVEMESSAGE/CHAN=S RTR show transactionRTR RTRRECEIVEMESSAGE/TIME=0 $ RTR RTR START RTRRTR RTRRECEIVEMESSAGE/CHANNEL=C/tim RTR RTRSTARTTX/CHAN=Centers commands at the server RTR show transactionApplication Programming Interfaces BrowserInterface Object-OrientedApplication Programming Interfaces Figure 4-1 RTR Browser InterfaceRTR C Example of object creation in an RTR server programinterface, see the RTR C Application Programmers Reference Manual and the RTR Application Design GuideExample of an open channel call in an RTR client program The RTR Environment The RTR System Management EnvironmentHandles all transactions and recovery Page Monitoring RTR ManagementTransaction RTR Monitor pictures or the RTR Monitor let you view thePartition The RTR Runtime EnvironmentManagement Figure 5-2 RTR Runtime Environment RTR Installation Guide Whats Next?RTR Release Notes RTR Migration Guide ifPage Glossary ACIDapplet applicationbranch broadcastcallout server channelcommon classes concurrent serverdata marshalling data objectendian frontend message primary processproperties property classesrollback routerRTR conﬁguration RTR environmentshadow standbytransaction transaction controllertransactional message two-phase committransactional shadowing Index Index-1Index-2