IBM SC34-7012-01 manual Failures that require CICS recovery processing

Forward recovery journal names are of the form DFHJnn where nn is a number in the range 1–99 and is obtained from the forward recovery log id (FWDRECOVLOG) in the FILE resource definition.

In this case, CICS creates a journal entry for the forward recovery log, which can be mapped by a JOURNALMODEL resource definition. Although this method enables user application programs to reference the log, and write user journal records to it, you are recommended not to do so. You should ensure that forward recovery log streams are reserved for forward recovery data only.

Note: You cannot use a CICS system log stream as a forward recovery log.

The VSAM recovery options or the CICS file control recovery options that you require to implement forward recovery are explained further in “Defining files as recoverable resources” on page 126.

For details of procedures for performing forward recovery, see Chapter 17, “Forward recovery procedures,” on page 187.

Forward recovery for non-VSAM resources

CICS does not provide forward recovery logging for non-VSAM resources, such as BDAM files. However, you can provide this support yourself by ensuring that the necessary information is logged to a suitable log stream. In the case of BDAM files, you can use the CICS autojournaling facility to write the necessary after-images to a log stream.

Failures that require CICS recovery processing

The following section briefly describes CICS recovery processing after a communication failure, transaction failure, and system failure.

Whenever possible, CICS attempts to contain the effects of a failure, typically by terminating only the offending task while all other tasks continue normally. The updates performed by a prematurely terminated task can be backed out automatically.

CICS recovery processing following a communication failure

Causes of communication failure include:

vTerminal failure

vPrinter terminal running out of paper

vPower failure at a terminal

vInvalid SNA status

vNetwork path failure

vLoss of an MVS image that is a member of a sysplex

There are two aspects to processing following a communications failure:

1.If the failure occurs during a conversation that is not engaged in syncpoint protocol, CICS must terminate the conversation and allow customized handling of the error, if required. An example of when such customization is helpful is for 3270 device types. This is described below.

8CICS TS for z/OS 4.1: Recovery and Restart Guide