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Compaq Reliable Transaction Router Failover and Recovery, Recovery Scenarios, Router Failover

Models: Reliable Transaction Router

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Failover and Recovery

Failover and Recovery

Failover and Recovery

	RTR provides several capabilities to ensure failover and recovery
	under several circumstances.
Router Failover	Frontend nodes automatically connect to another router if the
	one being used fails. This reconnection is transparent to the
	application.
	Routers are responsible for coordinating the two-phase commit
	for transactions. If the original router coordinating a transaction
	fails, backend nodes select another router that can ensure correct
	transaction completion.
Backend	Transactions in the process of being committed at the time of a
Restart	failure are recovered from RTR's disk journal. Recovery could be
Recovery	with a concurrent server, a standby server, or a restarted server
	created when the failed backend restarts.
	Correct ordering of the execution of transactions against the
	database is maintained.
Transaction	Transaction messages which are lost in transit are re-sent when
Message	possible. The frontend and backend nodes keep an in-memory
Replay	copy of all active messages for this purpose.
Link Failure	In the event of a communications failure, RTR tries to reconnect
Recovery	the link or links until it succeeds.

Recovery Scenarios

This section describes how RTR recovers from different hardware and software failure. For additional information on failure and recovery scenarios, see the RTR Application Design Guide.

3–2Reliability Features

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Compaq Reliable Transaction Router Failover and Recovery, Recovery Scenarios, Router Failover, Backend, Restart, Message

Contents

January Revision/Update Information This is a new manualReliable Transaction Router Getting Started 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 5 The RTR Environment 3 Reliability Features4 RTR Interfaces Glossary Index ExamplesFigures TablesPage Purpose of this Document PrefaceDocument Structure Related Documentation RTR CommandsRouter Installation For all usersConventions Reading PathReaders Comments New termApplication Programmer Figure 1 RTR Reading PathSystem Manager 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 ServersRecovery Failover and RecoveryRecovery Scenarios Router FailoverBackend Recovery Router Recovery Frontend Recovery Page RTR Interfaces RTR Management Station RTR Management Station RTR CREATE FACILITY DESIGN/ALLROLES=NODEA $ RTRRTR SHOW JOURNAL RTR SHOW FACILITYRTR RTRRECEIVEMESSAGE/TIME=0 RTR RTRRECEIVEMESSAGE/CHAN=SRTR show transaction $ RTR RTR START RTRenters commands at the server RTR RTRRECEIVEMESSAGE/CHANNEL=C/timRTR RTRSTARTTX/CHAN=C RTR show transactionInterface Application Programming InterfacesBrowser Object-OrientedApplication Programming Interfaces Figure 4-1 RTR Browser Interfaceinterface, see the RTR C Application Programmers Reference RTR CExample of object creation in an RTR server program 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 Transaction Monitoring RTRManagement RTR Monitor pictures or the RTR Monitor let you view thePartition The RTR Runtime EnvironmentManagement Figure 5-2 RTR Runtime Environment RTR Release Notes RTR Installation GuideWhats Next? RTR Migration Guide ifPage applet GlossaryACID applicationcallout server branchbroadcast channeldata marshalling common classesconcurrent server data objectendian frontend message properties primaryprocess property classesRTR conﬁguration rollbackrouter RTR environmenttransaction shadowstandby transaction controllertransactional message two-phase committransactional shadowing Index Index-1Index-2