EMS Manual

Configuring EMS
EMS Manual—426909-005
12-3
Log Files
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An alternate collector can run as a process pair, or it can run without a backup.
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Each alternate collector has a unique name, defined when the collector is started.
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An alternate collector is started by a TACL RUN command or by another process.
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The attributes associated with each alternate collector govern only the operation of
that collector.
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Attribute information can be specified as parameters in the TACL command and
passed to the alternate collector as STARTUP text. Some attributes directly control
the operation of the collector. Others control the operation of the log files for each
collector.

You can change the values of some attributes after the collector is started, either
by issuing the SPI CONTROL command or by running the EMSCCTRL program.

Each alternate collector can be opened by a maximum of 1873 event message
issuers and a maximum of 127 management programs (#ZSPI openers).
Log Files
Log files of the primary and alternate collectors are identical in structure. These log
files are disk files with the file code 843. Each collector opens its log files with
READ/WRITE access and PROTECTED exclusion mode. In addition to log files, each
collector defines configuration files (named ZZEVCONF) that provide a place to hold
log file tracking information.
All tasks associated with log switches are performed when the collector is idle (that is,
when there are no events to log). These tasks include purging and deallocating the old
log file and preallocating the next log file. Although this feature does not contribute to a
higher maximum sustained logging rate, it streamlines event logging and improves the
collector’s ability to handle bursts during log switches.
You can significantly improve the peak logging rate if events are blocked. For more
information about the BLOCKING attribute, see BLOCKING
on page 12-6.
Primary Collector Log Files
When a system is loaded, the primary collector starts entering event messages into log
files on the system volume. In addition to log files, the collector also uses two fixed files
on the system volume (the disk volume from which the system was loaded) to retain
log file and collector attributes. The system uses these files to restart logging after
system loads or problems with the normal logging volume.
When a system is loaded from the $SYSTEM.SYSnn subvolume, these files are
available for use by the primary collector:
Note. The LOGPREFIX keyword of the EMSACOLL program lets you rename the third
character in the prefix pattern of an alternate collector’s ZZEVCONF context file and
associated log files. For details, see EMSACOLL—Alternate Collector Program
on page 13-2.