Checkpoint Service Programmer’s Reference 6806800C47B September 2007
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Contents About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.1 1.2 1.3 1.4 2 2.2 2.3 2.4 2.5 Service Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.
Contents 4 Checkpoint Service Programmer’s Reference (6806800C47B)
List of Tables Table 1-1 Table 2-1 Table 2-2 Table 2-3 Table 2-4 Table B-1 Table B-2 Compliance Table - Checkpoint Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ncsCkptRegisterCkptArrivalCallback() Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . ncsCkptRegisterCkptArrivalCallback() Return Values . . . . . . . . . . . . . . . . . . . . . . . . . (*ncsCkptCkptArrivalCallback)() Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of Tables 6 Checkpoint Service Programmer’s Reference (6806800C47B)
List of Figures Figure 1-1 Checkpoint Service -Subparts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of Figures 8 Checkpoint Service Programmer’s Reference (6806800C47B)
About this Manual Overview of Contents This manual is divided into the following chapters and appendices. z Chapter 1, Introduction, on page 13 Provides an overview of the Cechpoint service functionilty and provides references to standard SAF documents. z Chapter 2, API Description, on page 17 Provides information that is required when writing applications that make use of the Checkpoint service. It also explains non-standard extensions that were added to the service.
About this Manual Abbreviation Definition MDS Message Distribution Service MIB Management Information Base NCS Netplane Core Services SAF Service Availability Forum Conventions The following table describes the conventions used throughout this manual.
About this Manual Summary of Changes This manual has been revised and replaces all prior editions. Part Number Publication Date Description 6806800C47A February 2007 First edition 6806800C47B September 2007 Minor text updates for Avantellis Release 3.0.2 Comments and Suggestions We welcome and appreciate your comments on our documentation. We want to know what you think about our manuals and how we can make them better.
About this Manual 12 Checkpoint Service Programmer’s Reference (6806800C47B)
Introduction 1.1 1 Overview The Checkpoint Service provides a facility for processes to record checkpoint data incrementally, which can be used to protect an application against failures. When recovering from fail-over or switch-over situations, or restart situations, the checkpoint data can be retrieved, and execution can be resumed from the state recorded before the failure. Checkpoints are cluster-wide entities that are designated by unique names.
Introduction 1.2 Models and Concepts Models and Concepts The Checkpoint service comprises three distributed subparts that maintain the cluster-wide checkpoint database.
Checkpoint Agent Introduction choose the CPND that oversees the active replica of a particular checkpoint via the invocation of the saCkptActiveReplicaSet() API. In all other cases, the CPD will designate the CPND that oversees the active replica. The CPND that oversees the active replica of a particular checkpoint will control all the operations on that checkpoint and it is not constrained to be present on the same node where the application resides.
Introduction 1.4 Related SAF Standard Documents Related SAF Standard Documents The document SAF-AIS-CKPT-B.01.01 is an SAF standard document. It provides the service definition of the Checkpoint service and can be found at the following location: http://www.saforum.org/apps/org/workgroup/twg/ais/download.php/1445/aisCkpt.B0101.
API Description 2.1 2 Service Extensions The current release of NCS Checkpoint Service provides one API and a callback function in addition to the APIs defined in the SAF-AIS Checkpoint Service document SAF-AIS-CKPTB.01.01. These APIs are defined as 'stand-alone' APIs so that other SAF-defined APIs are not disturbed, and compliance to SAF is not compromised. These extensions are defined to provide the hot-standby support to the Checkpoint Service user applications. 2.1.
API Description (*ncsCkptCkptArrivalCallback)() The following table lists possible return values of this call. Table 2-2 ncsCkptRegisterCkptArrivalCallback() Return Values 2.1.
Implementation Notes API Description If a callback of this form has been registered with the Checkpoint service via ncsCkptRegisterCkptArrivalCallback(), then it will be invoked whenever new or updated checkpoint replica data arrives for the checkpoint identified by checkpointHandle. The checkpoint writer is never called back. Also, applications that have not opened the checkpoint with the SA_CKPT_CHECKPOINT_READ flag are not called back.
API Description Time-out Arguments for Checkpoint Service APIs Creating extra replicas on the system manager node for non-collated checkpoints is an overhead. The advantage of a non-collocated checkpoint is that replica will be created in two places, no matter from how many nodes it is opened. 2.2.2 Time-out Arguments for Checkpoint Service APIs For all synchronous API calls, the application will provide the “timeout” argument.
Shared Memory Configuration 2.3.1 API Description Shared Memory Configuration NCS3.0 Checkpoint service uses the shared memory for storing the checkpoint replicas. Checkpoint service will manage the shared memory segments created by it for storing the checkpoint replicas. The shared memory requirements for storing the checkpoint replica can be derived from the checkpoint creation attributes supplied at the time of saCkptCheckpointOpen( ) or saCkptCheckpointOpenAsync( ) call using the formula.
API Description 2.5 Management Interface Management Interface SAF-CHK-SVC-MIB is defined by SA forum’s systems management WG. This MIB provides the manageable objects to access the cluster wide created checkpoint properties, location of the checkpoint replicas, version supported etc. This MIB also defines the traps to notify the errors like no more sections, sections available now etc. NCS Checkpoint Service implements a draft version of SAF-CKPT-SVC-MIB, which aligns with B.01.01 version of CKPT.
A Sample Application A.1 A Overview The sample application provided here consists of two application processes that use the Checkpoint service APIs to ‘write’ to a checkpoint, and ‘read’ the checkpoint data written by the first application process. A.2 Run the Checkpoint Service Demo This sample application assumes that the NCS software is installed and running on the target system. Refer to the Avantellis 3000 Series Rel. 3.0 User’ s Guide for information on how to install the NCS software.
Sample Application A.3 Sample Application Output Sample Application Output MESSAGE_ WRITER Ckpt Initialising being called .... Ckpt Open being called .... PASSED PASSED Ckpt Active Replica Set being called .... Ckpt Section Create being called .... PASSED PASSED Ckpt Write being called with data: The Checkpoint Service provides a facility for processes to record checkpoint data .... PASSED Ckpt Synchronize being called .... Ckpt Unlink being called .... PASSED Ckpt Close being called ....
B Related Documentation B.1 B Motorola Embedded Communications Computing Documents The Motorola publications listed below are referenced in this manual. You can obtain electronic copies of Embedded Communications Computing (ECC) publications by contacting your local Motorola sales office or by visiting ECC’s World Wide Web literature site: http://www.motorola.com/computer/literature. This site provides the most up-to-date copies of ECC product documentation.
Related Documentation B.2 Related Specifications Related Specifications For additional information, refer to the following table for related specifications. As an additional help, a source for the listed document is provided. Please note that, while these sources have been verified, the information is subject to change without notice.
