Allocation Options for Alternative Log Data Sets on z/OS
Allocation Options for Alternative Log Data Sets on z/OS
On z/OS, PowerExchange dynamically allocates alternative log data sets to log messages from PowerExchange jobs and started tasks if you define the TRACING statement in the DBMOVER configuration file. Alternatively, you can specify a DTLLOG DD statement in the JCL for the PowerExchange jobs and started tasks that issue messages.
Use any of the following methods to allocate alternative log data sets on z/OS:
Dynamic allocation
. If you define the TRACING statement, PowerExchange dynamically allocates log data sets except for any PowerExchange job or started task for which you add a DTLLOG
nn
DD statement in the JCL. To name the dynamically allocated log data sets, PowerExchange uses the PFX parameter value in the TRACING statement in conjunction with the file-naming convention for the PowerExchange component and platform. To determine the number of log data sets, PowerExchange uses the FILENUM parameter value in the TRACING statement.
Single DTLLOG01 DD statement with SYSTOUT=*
. To simplify configuration and make finding message output for a specific job execution easier, Informatica recommends that you define a single DTLLOG01 DD statement that points to SYSOUT=* in the JCL for PowerExchange jobs and started tasks that issue messages. When you run one of these jobs or tasks, all of its message output is written to a single SYSOUT data set. In this case, PowerExchange does not use the PFX, APPEND, FILENUM, and VIEW parameters from the TRACING statement. However, if you have other jobs and started tasks that use dynamic allocation, PowerExchange honors the PFX, APPEND, FILENUM, and VIEW parameters for these jobs and tasks.
DTLLOG
nn
DD statements with different data set names
. You can specify DTLLOG
nn
DD statements with different data set names in the JCL for PowerExchange jobs or started tasks. You must specify the PFX parameter in the TRACING statement, but PowerExchange ignores it. Also, PowerExchange ignores the FILENUM parameter for all jobs that include the DTLLOG
nn
DD statements. To switch to another alternative log file when the current one becomes full, PowerExchange uses the same round-robin algorithm as it uses for dynamically allocated log data sets.
The variable
nn
is a number from 01 through 99. You can specify up to 99 DTLLOG
nn
DD statements.
Single DTLLOG01 DD statement that specifies a GDG
. To use a GDG for alternative logging on
z/OS
, specify
GDG(0)
and DISP=SHR in a single DTLLOG01 DD statement in the PowerExchange Listener JCL. Also, allocate and create at least one generation of the GDG before starting the PowerExchange Listener.
By using
GDG(0)
, you can use
APPEND=Y
in the TRACING statement to enable PowerExchange to resume logging messages to the current generation. Also, you can use
VIEW=Y
to view log records in the GDG while the PowerExchange Listener task is active. If you specify
APPEND=N
, PowerExchange creates a new generation when the PowerExchange Listener starts.
PowerExchange does not limit the number of GDG generations. The FILENUM parameter in the TRACING statement is ignored. Instead, the LIMIT value in the GDG definition limits the number of generations. When this limit is reached, the operating system automatically removes the oldest generation from the GDG and deletes it if the SCRATCH parameter is defined for the GDG.
You cannot use DFSMS compression for alternative log data sets.
Before using DTLLOG
nn
DD statements, review the following considerations:
You still must specify the DTLLOG DD statement for the following purposes:
To write initial startup messages
To write messages if PowerExchange encounters an error allocating or writing to alternative log data sets
The DTLLOG DD statement can point to a permanent data set or a SYSOUT data set. Informatica recommends that you specify use SYSOUT=* as a safeguard against any failures with alternative log files and to prevent the out-of-space conditions.
Unless you specify a DTLLOG
nn
DD statement in the JCL, PowerExchange dynamically allocates alternative log files.
To prevent loss of PowerExchange log and trace information, use unique data set names for each PowerExchange job with DTLLOG
nn
DD statements.
If you use a GDG for alternative logging, add a single DTLLOG01 DD statement that specifies GDG(0) in the JCL.
PowerExchange jobs and started tasks that write to alternative log files include the PowerExchange Listener, PowerExchange Condense, PowerExchange Agent, and netport jobs. Also, the Adabas, IDMS, and IMS log-based ECCRs and the Datacom table-based ECCR can use alternative log files.
However, the PowerExchange Logger, batch VSAM ECCR, CICS/VSAM ECCR, and IMS synchronous ECCR do not write messages to the PowerExchange message log or alternative log files.