pmnewlog may be used to stop and restart a running instance of
pmlogger(1). This is most useful for managing multiple sets of
Performance Co-Pilot (PCP) archive logs. These archive logs record
the history of performance metric values that may be ``played back''
by other PCP tools, and they form the basis of the VCR paradigm and
retrospective performance analysis services common to the PCP
In normal usage, pmnewlog would be executed by cron(1) in the wee
hours to terminate one PCP archive log and start another, i.e. to
perform log rotation.
Even more common, would be the execution of pmnewlog from the PCP
archive management script pmlogger_daily(1). In this case, direct
end-user execution of pmnewlog is most unlikely.
The mandatory argument archive is the base name for the physical
files that will constitute the new archive log.
The pmlogger instance to be stopped and restarted must be running on
the same system as pmnewlog and is either the primary logger (the
default) or the logger with pid as specified by the -p option.
If the -n option is specified, then pmnewlog will use the namespace
in the pmnsfile, rather than the default Performance Metrics Name
If no -c option is specified, pmnewlog will use pmlc(1) to connect to
the running pmlogger(1) and so determine all those metrics and
instances that are subject to mandatory logging or advisory on
logging, and the associated logging frequencies. This information is
used to synthesize a new pmlogger(1) configuration file. If the -n
option is specified, it will also be used for these interactions with
If the -c option is specified, pmlogger(1) will be restarted with
configfile as the configuration file. Normally configfile would be
the same configuration file used to start pmlogger(1) in the first
place, however note that since pmlogger(1) is restarted, any changes
to the logging status made using pmlc(1) will be lost, unless these
have also been reflected in changes to configfile.
If configfile does not exist, then a search is made in the directory
$PCP_VAR_DIR/config/pmlogger for a file of the same name, and if
found that file is used, e.g. if config.mumble does not exist in the
current directory and the file
$PCP_VAR_DIR/config/pmlogger/config.mumble does exist, then -cconfig.mumble and -c $PCP_VAR_DIR/config/pmlogger/config.mumble are
Access controls specifications for the new pmlogger(1) instance may
optionally be provided via the -a option. The contents of accessfile
should start with the literal token [access] and conform to the
syntax of the access controls section as described for pmlogger(1).
The -C option may be used to save the configuration file that
pmnewlog passes to the newly launched pmlogger(1).
If the pmlogger(1) instance needs to be started under the control of
pmsocks(1) to connect to a pmcd through a firewall, the -s option may
The -V option enables verbose reporting of the activity. By default
no output is generated unless some error or warning condition is
The -N option enables a ``show me'' mode, where the actions are
echoed, but not executed, in the style of ``make -n''. Using -N in
conjunction with -V maximizes the diagnostic capabilities for
The other pmlogger options are as described for pmlogger(1). Note
that pmnewlog does not support the following options of pmlogger(1).
-h hostpmnewlog determines the host to which the new pmlogger(1)
should connect based upon the current host connection for the
The new pmlogger(1) is expected to be long running, and the -s
option of pmnewlog takes precedence.
The new pmlogger(1) is expected to be long running
The new pmlogger will always create the latest version PCP
archive format, and the -V option of pmnewlog takes
-x fd The launched pmlogger cannot be controlled by
The following sh(1) script could be executed by root via cron(1) to
start a new set of archive logs for the primary logger each evening.
A more complete version of this script may be found in
$PCP_BINADM_DIR/pmlogger_daily, and is documented in the manual page
# start new logs for PCP primary logger on this host
# standard place for logs
# each new log is named yymmdd.hh.mm
# do it
[ ! -d $LOGDIR ] && mkdir -p $LOGDIR
$PCP_BINADM_DIR/pmnewlog -l $LOGDIR/pmlogger.log $LOGDIR
metadata (metric descriptions, instance domains, etc.) for
the archive log
archive.0 initial volume of metrics values (subsequent volumes have
suffixes 1, 2, ...)
temporal index to support rapid random access to the other
files in the archive log
sample script to rotate archives for a number of loggers
Environment variables with the prefix PCP_ are used to parameterize
the file and directory names used by PCP. On each installation, the
file /etc/pcp.conf contains the local values for these variables.
The $PCP_CONF variable may be used to specify an alternative
configuration file, as described in pcp.conf(5).
Due to the precious nature of the archive logs, pmnewlog is rather
paranoid in its checking and validation, and will try very hard to
ensure that an appropriately configured pmlogger(1) can be restarted,
before terminating the existing pmlogger(1).
As a consequence of this checking, pmnewlog tends to generate rather
verbose error and warning messages.
If no configfile is specified, the method for synthesizing a
configuration file using a pmlc(1) connection to the existing
pmlogger(1) is, of necessity, incomplete. In particular, for metrics
with dynamic underlying instance domains, it is not possible to
identify a configuration that logs all instances of a metric all of
the time, so rather the synthesized configuration file requests the
continued logging of the set of instances that exist at the time
pmlogger(1) is interrogated by pmnewlog.
If this situation is a concern, a fixed configuration file should be
used, and passed to pmnewlog via the -c option.
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
firstname.lastname@example.org. This page was obtained from the project's upstream
Git repository ⟨git://git.pcp.io/pcp⟩ on 2017-03-13. If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page, or
you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
Performance Co-Pilot PCP PMNEWLOG(1)