Log recording data set
Log recording data set (LOGREC) is a set of records (stored in a data set or in a log stream) that contain hardware and software error descriptions that relate to specific events.
z/OS V2R2 introduces updates for LOGREC.
This chapter includes the following topics:
3.1 LOGREC overview
When errors occur, the system records information about the error in the LOGREC data set or the LOGREC log stream. The records can describe hardware or software errors.
If you have a small single system, you can select a data set as the repository for the error records. However, if you have a sysplex, it is advantageous to reference a single source of error records that are appertaining to each system in the sysplex. In this case, you might prefer to chose one coupling facility log stream.
The following typical maintenance activities require an initial program load (IPL):
•Performing hardware, software, or operational maintenance on the DASD device on which the LOGREC data set is allocated.
•Switch from the LOGSTREAM option to the DATASET option after a System Logger outage, without having the LOGREC data set pre-allocated.
•Resize the SYS1.Logrec data set.
•Save an old Sys1.Logrec data set and switch to a new data set.
A more flexible solution is required to alleviate potential threats to availability. The following typical scenarios are the drivers for the enhancements that are introduced with z/OS V2R2:
•Enhance the SETLOGRC command to allow the following uses:
– When switching to the DATASET option, allocate the data set. This action occurs even if your system is restarted with the LOGSTREAM or IGNORE options specified.
– When switching from the DATASET option, deallocate the data set.
– Allow specification of the DATASET or LOGSTREAM options resource.
•Enhance the IEASYSxx LOGREC= keyword to specify the log stream name.
The goal is to reduce the risk of maintenance activities by lowering availability levels and to provide a more flexible approach in the operational management of LOGREC. Ideally, new automation procedures might be introduced to use this flexibility to provide smoother operational running.
3.2 Changing the LOGREC specification
z/OS V2R2 introduces more functionality to the SETLOGRC command, as shown in Figure 3-1.
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SETLOGRC {LOGSTREAM|DATASET|IGNORE|LOGSTREAM=lsname|DATASET=dsname}
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Figure 3-1 SETLOGRC command syntax
The SETLOGRC command cannot be abbreviated. The LOGSTREAM option can be abbreviated to LS. In addition, the DATASET option can be abbreviated to DS.
You might want to issue this command to change the medium or to retain the same medium but use a different location by specifying a new name in the DATASET= or LOGSTREAM= parameters.
After the command is processed, one of the following results occur:
•If the change of medium is successful, the system issues an IFB097I message to indicate the change and the new medium to the requesting console.
•If the change is to the DATASET parameter:
– If the change of medium is to DATASET and the system was not originally initialized with a data set specified, the system now dynamically allocates and opens the specified data set. If no data set name is provided, LOGREC defaults to the use of SYS1.LOGREC. If the system fails to open on the LOGREC data set, it issues the IFB110I, IFB112I, and IFB099I messages.
– If the current medium is DATASET and DATASET is requested with a new data set name, LOGREC closes and deallocates the old data set. It then allocates and opens the new data set for LOGREC recording.
– If the current medium is LOGSTREAM and DATASET is requested, LOGREC disconnects from the log stream. It then allocates and opens the data set for LOGREC recording. If problems arise when allocating the data set, LOGREC attempts to revert to log stream recording.
•If the change is to the IGNORE parameter:
– If the current setting is IGNORE and IGNORE is requested, LOGREC issues the IFB096I message to the starting console to indicate that the wanted medium is the current setting.
– If the wanted setting is to IGNORE, LOGREC error and environmental records are not recorded and are not provided in an ENF 36 signal.
– If the current medium is DATASET and IGNORE is requested, LOGREC closes and deallocates the LOGREC data set.
– If the current medium is LOGSTREAM and IGNORE is requested, LOGREC disconnects from the log stream.
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Suggestion: Use the IGNORE setting only in non-critical environments.
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•If the change is to the LOGSTREAM parameter:
– If the wanted setting is to LOGSTREAM and the connection to the log stream succeeds, the system issues the IFB097I message to indicate the successful change of medium from LOGSTREAM to LOGSTREAM.
If the change of medium is unsuccessful, the system issues the IFB099I message. The system also issues the IFB100E message to indicate that the system logger is unavailable. LOGREC error and environmental records are buffered internally until the system logger becomes available. The buffer wraps around when the buffers are full.
– If the connection is successful or when system logger and the log stream are available for writing, LOGREC writes records (including any buffered records) to the log stream.
– If the current medium is DATASET and LOGSTREAM is requested, LOGREC closes and deallocates the LOGREC data set, then connects to the log stream.
– If the current medium is LOGSTREAM and LOGSTREAM is requested, LOGREC disconnects from and then reconnects to the log stream. If a new log stream name is requested, LOGREC disconnects from the old log stream and connects to the new log stream.
Example 3-1 shows samples of the SETLOGRC command.
Example 3-1 Example of SETLOGRC commands
SETLOGRC LOGSTREAM=LOGREC.SYSPLEX1
SETLOGRC DATASET=MVSA.LOGREC
Example 3-2 shows the IEASYSxx LOGREC= parameter that is used at initial load to specify the option.
Example 3-2 Example of LOGREC parameter at IEASYSxx
LOGREC=LOGSTREAM=LOGREC.GROUP2
LOGREC=LS=SYS1.LOGREC.MVSX
The values for the dsname and lsname options can contain system symbols. When the dsname option is used, only one data set can be specified.
3.3 New messages
z/OS V2R2 introduces the following messages:
Explanation: When you issued the SETLOGRC command to change the LOGREC recording medium to DATASET, the system encountered a problem.
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IFB110I UNABLE TO function LOGREC DATASET, NAME: data-set-name, RETCODE: retcode RSNCODE rsncode
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Figure 3-2 Message IFB11OI
Explanation: This message contains dynamic allocation messages when the allocation of the LOGREC data set has problems after you use a SETLOGRC command.
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IFB112I dynamic allocation messages
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Figure 3-3 Message IFB112I
For more information, about the message fields, see z/OS MVS System Messages, Vol 8 (IEF-IGD), SA38-0675-03.
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