Provided by: pcp_3.8.12ubuntu1_amd64 
NAME
pmlogger - create archive log for performance metrics
SYNOPSIS
pmlogger [-c configfile] [-h host] [-l logfile] [-L] [-m note] [-n pmnsfile] [-P] [-r] [-s endsize] [-t
interval] [-T endtime] [-u] [-U username] [-v volsize] [-V version] [-x fd] archive
DESCRIPTION
pmlogger creates the archive logs of performance metric values that may be ``played back'' by other
Performance Co-Pilot (see PCPIntro(1)) tools. These logs form the basis of the VCR paradigm and
retrospective performance analysis services common to the PCP toolkit.
The mandatory argument archive is the base name for the physical files that constitute an archive log.
The -V option specifies the version for the archive that is generated. By default a version 2 archive is
generated, and the only value currently supported for version is 2.
Unless directed to another host by the -h option, pmlogger will contact the Performance Metrics Collector
Daemon (PMCD) on the local host and use that as the source of the metric values to be logged.
To support the required flexibility and control over what is logged and when, pmlogger maintains an
independent two level logging state for each instance of each performance metric. At the first
(mandatory) level, logging is allowed to be on (with an associated interval between samples), or off or
maybe. In the latter case, the second (advisory) level logging is allowed to be on (with an associated
interval between samples), or off.
The mandatory level allows universal specification that some metrics must be logged, or must not be
logged. The default state for all instances of all metrics when pmlogger starts is mandatory maybe and
advisory off.
Use pmlc(1) to interrogate and change the logging state once pmlogger is running.
If a metric's state is mandatory (on or off) and a request is made to change it to mandatory maybe, the
new state is mandatory maybe and advisory off. If a metric's state is already advisory (on or off) and a
request is made to change it to mandatory maybe, the current state is retained.
It is not possible for pmlogger to log specific instances of a metric and all instances of the same
metric concurrently. If specific instances are being logged and a request to log all instances is made,
then all instances of the metric will be logged according to the new request, superseding any prior
logging request for the metric. A request to log all instances of a metric will supersede any previous
request to log all instances. A request to log specific instances of a metric when all instances are
already being logged is refused. To do this one must turn off logging for all instances of the metric
first. In each case, the validity of the request is checked first; for example a request to change a
metric's logging state to advisory on when it is currently mandatory off is never permitted (it is
necessary to change the state to mandatory maybe first).
Optionally, each system running pmcd(1) may also be configured to run a ``primary'' pmlogger instance.
Like pmcd(1), this pmlogger instance is launched by $PCP_RC_DIR/pcp, and is affected by the files
$PCP_SYSCONF_DIR/pmlogger (use chkconfig(1M) to activate or disable the primary pmlogger instance),
$PCP_SYSCONF_DIR/pmlogger/pmlogger.options (command line options passed to the primary pmlogger) and
$PCP_SYSCONF_DIR/pmlogger/config.default (the default initial configuration file for the primary
pmlogger).
The primary pmlogger instance is identified by the -P option. There may be at most one ``primary''
pmlogger instance on each system with an active pmcd(1). The primary pmlogger instance (if any) must be
running on the same host as the pmcd(1) to which it connects, so the -h and -P options are mutually
exclusive.
When launched as a non-primary instance, pmlogger will exit immediately if the configuration file causes
no metric logging to be scheduled. The -L option overrides this behavior, and causes a non-primary
pmlogger instance to ``linger'', presumably pending some future dynamic re-configuration and state change
via pmlc(1). pmlogger will also linger without the -L option being used if all the metrics to be logged
are logged as once only metrics. When the once only metrics have been logged, a warning message will be
generated stating that the event queue is empty and no more events will be scheduled.
By default all diagnostics and errors from pmlogger are written to the file pmlogger.log in the directory
where pmlogger is launched. The -l option may be used to override the default behavior. If the log file
cannot be created or is not writable, output is written to standard error instead.
If specified, the -s option instructs pmlogger to terminate after a certain size in records, bytes or
time units has been accumulated. If endsize is an integer then endsize records will be written to the
log. If endsize is an integer suffixed by b or bytes then endsize bytes of the archive data will be
written out (note, however, that archive log record boundaries will not be broken and so this limit may
be slightly surpassed). Other viable file size units include: K, Kb, Kbyte, Kilobyte for kilobytes and
M, Mb, Mbyte, Megabyte for megabytes and G, Gb, Gbyte, Gigabyte for gigabytes. These units may be
optionally suffixed by an s and may be of mixed case. Alternatively endsize may be an integer or a
floating point number suffixed using a time unit as described in PCPIntro(1) for the interval argument
(to the standard PCP -t command line option).
Some examples of different formats:
-s 100
-s 100bytes
-s 100K
-s 100Mb
-s 10Gbyte
-s 10mins
-s 1.5hours
The default is for pmlogger to run forever.
The -r option causes the size of the physical record(s) for each group of metrics and the expected
contribution of the group to the size of the PCP archive for one full day of collection to be reported in
the log file. This information is reported the first time each group is successfully written to the
archive.
The -U option specifies the user account under which to run pmlogger. The default is the current user
account for interactive use. When run as a daemon, the unprivileged "pcp" account is used in current
versions of PCP, but in older versions the superuser account ("root") was used by default.
The log file is potentially a multi-volume data set, and the -v option causes pmlogger to start a new
volume after a certain size in records, bytes, or time units has been accumulated for the current volume.
The format of this size specification is identical to that of the -s option (see above). The default is
for pmlogger to create a single volume log. Additional volume switches can also be forced asynchronously
by either using pmlc(1) or sending pmlogger a SIGHUP signal (see below). Note, if a scheduled volume
switch is in operation due to the -v option, then its counters will be reset after an asynchronous
switch.
Independent of any -v option, each volume of an archive is limited to no more than 2^31 bytes, so
pmlogger will automatically create a new volume for the archive before this limit is reached.
Normally pmlogger operates on the distributed Performance Metrics Name Space (PMNS), however if the -n
option is specified an alternative local PMNS is loaded from the file pmnsfile.
Under normal circumstances, pmlogger will run forever (except for a -s option or a termination signal).
The -T option may be used to limit the execution time using the format of time as prescribed by
PCPIntro(1).
Some examples of different formats:
-T 10mins
-T '@ 11:30'
From this it can be seen that -T 10mins and -s 10mins perform identical actions.
When pmlogger receives a SIGHUP signal, the current volume of the log is closed, and a new volume is
opened. This mechanism (or the alternative mechanism via pmlc(1)) may be used to manage the growth of
the log files - once a log volume is closed, that file may be archived without ill-effect on the
continued operation of pmlogger. See also the -v option above.
The buffers for the current log may be flushed to disk using the flush command of pmlc(1), or by sending
pmlogger a SIGUSR1 signal or by using the -u option (the latter forces every log write to be unbuffered).
This is useful when the log needs to be read while pmlogger is still running.
When launched with the -x option, pmlogger will accept asynchronous control requests on the file
descriptor fd. This option is only expected to be used internally by PCP applications that support
``live record mode''.
The -m option allows the string note to be appended to the map file for this instance of pmlogger in the
$PCP_TMP_DIR/pmlogger directory. This is currently used internally to document the file descriptor (fd)
when the -x option is used, or to indicate that this pmlogger instance was started under the control of
pmlogger_check(1).
CONFIGURATION FILE SYNTAX
The configuration file may be specified with the -c option. If it is not, configuration specifications
are read from standard input.
If configfile does not exist, then a search is made in the directory $PCP_SYSCONF_DIR/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_SYSCONF_DIR/pmlogger/config.mumble does exist, then -c config.mumble and -c
$PCP_SYSCONF_DIR/pmlogger/config.mumble are equivalent.
The syntax for the configuration file is as follows.
1. Words are separated by white space (space, tab or newline).
2. The symbol ``#'' (hash) introduces a comment, and all text up to the next newline is ignored.
3. Keywords (shown in bold below) must appear literally (i.e. in lower case).
4. Each specification begins with the optional keyword log, followed by one of the states mandatory
on, mandatory off, mandatory maybe, advisory on or advisory off.
5. For the on states, a logging interval must follow using the syntax ``once'', or ``default'', or
``every N timeunits'', or simply ``N timeunits'' - N is an unsigned integer, and timeunits is one
of the keywords msec, millisecond, sec, second, min, minute, hour or the plural form of one of the
above.
Internal limitations require the interval to be smaller than (approximately) 74 hours. An
interval value of zero is a synonym for once. An interval of default means to use the default
logging interval of 60 seconds; this default value may be changed to interval with the -t command
line option.
The interval argument follows the syntax described in PCPIntro(1), and in the simplest form may be
an unsigned integer (the implied units in this case are seconds).
6. Following the state and possible interval specifications comes a ``{'', followed by a list of one
or more metric specifications and a closing ``}''. The list is white space (or comma) separated.
If there is only one metric specification in the list, the braces are optional.
7. A metric specification consists of a metric name optionally followed by a set of instance names.
The metric name follows the standard PCP naming conventions, see pmns(5), and if the metric name
is a non-leaf node in the PMNS (see pmns(5)), then pmlogger will recursively descend the PMNS and
apply the logging specification to all descendent metric names that are leaf nodes in the PMNS.
The set of instance names is a ``['', followed by a list of one or more space (or comma) separated
names, numbers or strings, and a closing ``]''. Elements in the list that are numbers are assumed
to be internal instance identifiers, other elements are assumed to be external instance
identifiers - see pmGetInDom(3) for more information.
If no instances are given, then the logging specification is applied to all instances of the
associated metric.
8. There may be an arbitrary number of logging specifications.
9. Following all of the logging specifications, there may be an optional access control section,
introduced by the literal token [access]. Thereafter come access control rules of the form
``allow hostlist : operation ;'' and ``disallow hostlist : operation ;''.
The base operations are advisory, mandatory and enquire. In all other aspects, these access
control statements follow the syntactic and semantic rules defined for the access control
mechanisms used by PMCD and are fully documented in pmcd(1).
EXAMPLES
For each PCP utility, there is a sample pmlogger configuration file that could be used to create an
archive log suitable for replaying with that tool (i.e. includes all of the performance metrics used by
the tool). For a tool named foo this configuration file is located in
$PCP_SYSCONF_DIR/pmlogger/config.foo.
The following is a simple default configuration file for a primary pmlogger instance, and demonstrates
most of the capabilities of the configuration specification language.
log mandatory on once { hinv.ncpu hinv.ndisk }
log mandatory on every 10 minutes {
disk.all.write
disk.all.read
network.interface.in.packets [ "et0" ]
network.interface.out.packets [ "et0" ]
nfs.server.reqs [ "lookup" "getattr" "read" "write" ]
}
log advisory on every 30 minutes {
environ.temp
pmcd.pdu_in.total
pmcd.pdu_out.total
}
[access]
disallow * : all except enquire;
allow localhost : mandatory, advisory;
FILES
archive.meta
metadata (metric descriptions, instance domains, etc.) for the archive log
archive.0 initial volume of metrics values (subsequent volumes have suffixes 1, 2, ...)
archive.index
temporal index to support rapid random access to the other files in the archive log
$PCP_TMP_DIR/pmlogger
pmlogger maintains the files in this directory as the map between the process id of the
pmlogger instance and the IPC port that may be used to control each pmlogger instance (as used
by pmlc(1))
$PCP_SYSCONF_DIR/pmlogger/config.default
default configuration file for the primary logger instance launched from $PCP_RC_DIR/pcp
$PCP_SYSCONF_DIR/pmlogger/config.*
assorted configuration files suitable for creating logs that may be subsequently replayed with
the PCP visualization and monitoring tools
$PCP_LOG_DIR/pmlogger/hostname
Default directory for PCP archive files for performance metric values collected from the host
hostname.
./pmlogger.log
(or $PCP_LOG_DIR/pmlogger/hostname/pmlogger.log when started automatically by either
$PCP_RC_DIR/pcp or one of the pmlogger(1) monitoring scripts such as pmlogger_check(1))
all messages and diagnostics are directed here
$PCP_RC_DIR/pcplocal
contains ``hooks'' to enable automatic restart at system boot time
ENVIRONMENT
Normally pmlogger creates a socket to receive control messages from pmlc(1) on the first available TCP/IP
port numbered 4330 or higher. The environment variable PMLOGGER_PORT may be used to specify an
alternative starting port number.
PCP ENVIRONMENT
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).
SEE ALSO
PCPIntro(1), pmcd(1), pmdumplog(1), pmlc(1), pmlogger_check(1), pcp.conf(5), pcp.env(5) and pmns(5).
DIAGNOSTICS
The archive logs are sufficiently precious that pmlogger will not truncate an existing physical file. A
message of the form
__pmLogNewFile: "foo.index" already exists, not over-written
__pmLogCreate: File exists
indicates this situation has arisen. You must explicitly remove the files and launch pmlogger again.
There may be at most one primary pmlogger instance per monitored host; attempting to bend this rule
produces the error:
pmlogger: there is already a primary pmlogger running
Various other messages relating to the creation and/or deletion of files in $PCP_TMP_DIR/pmlogger suggest
a permission problem on this directory, or some feral files have appeared therein.