Provided by: pcp-gui_5.3.6-1build1_amd64 
NAME
pmsnap - generate performance summary snapshot images
SYNOPSIS
$PCP_BINADM_DIR/pmsnap [-NV?] [-c configs] [-C dir] [-f format] [-n names] [-o dir]
DESCRIPTION
pmsnap is a shell script that is normally run periodically from crontab(1) to generate graphic images of
pmchart(1) performance charts. These images can be in any of the supported pmchart formats, including
png, bmp, and jpeg, and may be incorporated into the content offered by the local web server. By default
pmsnap generates no textual output unless some error or warning condition is encountered.
pmsnap generates images according to its control file, $PCP_PMSNAPCONTROL_PATH (or dir/control if the -C
option is specified), and uses archive logs created by pmlogger(1) or PCP archive folios created by
pmafm(1) and pmlogger_check(1). Before attempting to configure pmsnap, it is strongly recommended that
pmlogger be configured according to the descriptions in pmlogger_daily(1), pmlogger_check(1) and
pmlogger(1).
Once pmlogger has been configured, it is necessary to configure pmsnap as follows;
1. Edit the control file $PCP_PMSNAPCONTROL_PATH. The syntax of this file is described in the
comment at the head of the file and an example is supplied for one and twelve hour "Summary"
performance charts for the local host. Suitable arguments for pmchart are also described in the
comment. The user should consult pmchart for further details. Note that when pmsnap is run, it
globally substitutes the string LOCALHOSTNAME with the name of the local host in the control file.
2. Test the configuration by running
$PCP_BINADM_DIR/pmsnap.
Without any arguments pmsnap will process every non-comment line in $PCP_PMSNAPCONTROL_PATH. The
output images will be placed in the files named in the first field of each line in the control
file, with the file format appended if necessary. If these file names do not start with / or .
then they are assumed relative to dir, as specified with the -o option. The default dir is the
current directory. Note that if pmlogger has only been recently started (within about the last 15
minutes), snapshot images may not be produced and no error messages will be issued - the reason is
that pmchart can not use very short archives and hence, neither can pmsnap. For debugging
purposes the -V flag should be used.
3. Add an appropriate entry for pmsnap in the root user's crontab. An example is supplied in
$PCP_VAR_DIR/config/pmlogger/crontab.
4. Incorporate the pmsnap images into the local WWW content. Usually, WWW pages use images that are
relative to a particular document root, so it is often convenient to use the -o command line
option to specify a sub-directory of the local WWW content, and then create a web page in this
directory that shows the snapshot images with text and other content appropriate to the local
environment.
A sample HTML page, suitable for the Summary snapshot may be found in
$PCP_VAR_DIR/config/pmsnap/Summary.html.
Although pmsnap attempts to flush stdio(3) output buffers in the relevant pmlogger processes before
generating snapshots images, this may fail for assorted reasons and no error message will be given.
pmsnap should not be invoked immediately after pmlogger_daily has rolled the logs because the new archive
logs will be too short to obtain meaningful results. Note however that pmsnap will not report errors
from pmchart about not being able to comply with the -A option on very short archives. In these cases no
error will be reported and no output images will be produced.
OPTIONS
The available command line options are:
-c config-pattern
Only process lines in the control file which match the config-pattern regular expression in the
Config column.
-C dir
The control file is located in the directory dir rather than in the default $PCP_PMSNAPCONTROL_PATH
location.
-f format
Set output image format. The defaults format is png.
-n name-pattern
Only process lines in the control file which match the name-pattern regular expression (see
egrep(1)) in the Name column.
-N Enable 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 debugging.
-o dir
The output images having file names which do not start with / or . will be placed in a directory
relative to dir, otherwise the output directory is relative to the current directory (i.e. the
default value for dir is ./). Note that dir must be a writable directory path and may be on an NFS
or CIFS file system.
-V Enable verbose mode.
-? Display usage message and exit.
When either -n or -c are used, pmsnap will only process lines in the control file which match all the
supplied patterns. If no patterns are given, then all lines will be processed. These arguments allow
multiple entries for pmsnap in crontab so that different performance summary images can be generated at
different times or with different frequencies.
FILES
$PCP_PMSNAPCONTROL_PATH
pmsnap control file
$PCP_VAR_DIR/config/pmsnap/Summary
summary view for pmchart
$PCP_VAR_DIR/config/pmsnap/Summary.html
sample HTML page for summary snapshot
$PCP_LOG_DIR/pmlogger/<hostname>/Latest
PCP archive folio for the host hostname, as generated by pmlogger_check
$PCP_VAR_DIR/config/pmlogger/crontab
example crontab entry
SEE ALSO
cron(1), crontab(1), egrep(1), pmafm(1), pmchart(1), pmlc(1), pmlogger(1) and pmlogger_daily(1).
Performance Co-Pilot PMSNAP(1)