PMLOGGER(1)PMLOGGER(1)NAMEpmlogger - create archive log for performance metrics
SYNOPSIS
$PCP_BINADM_DIR/pmlogger [-c configfile] [-h host] [-l logfile] [-L]
[-m note] [-n pmnsfile] [-P] [-r] [-s endsize] [-t interval] [-T end‐
time] [-u] [-v volsize] [-V version] [-x fd] archive
DESCRIPTIONpmlogger 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 cur‐
rently 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 /etc/con‐
fig/pmlogger (use chkconfig(1M) to activate or disable the primary
pmlogger instance), /etc/config/pmlogger.options (command line options
passed to the primary pmlogger) and $PCP_VAR_DIR/config/pmlogger/con‐
fig.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 pmlog‐
ger 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, Kilo‐
byte 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 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 PCPIn‐
tro(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 alterna‐
tive 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_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 -c config.mumble and -c $PCP_VAR_DIR/config/pmlogger/con‐
fig.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, fol‐
lowed by one of the states mandatory on, mandatory off, manda‐
tory maybe, advisory on or advisory off.
5. For the on states, a logging interval must follow using the syn‐
tax ``once'', or ``default'', or ``every N timeunits'', or sim‐
ply ``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 syn‐
onym 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 PCPIn‐
tro(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) sepa‐
rated. If there is only one metric specification in the list,
the braces are optional.
7. A metric specification consists of a metric name optionally fol‐
lowed by a set of instance names. The metric name follows the
standard PCP naming conventions, see pmns(4), and if the metric
name is a non-leaf node in the PMNS (see pmns(4)), then pmlogger
will recursively descend the PMNS and apply the logging specifi‐
cation 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 : oper‐
ation ;''.
The base operations are advisory, mandatory and enquire. In all
other aspects, these access control statements follow the syn‐
tactic and semantic rules defined for the access control mecha‐
nisms 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_VAR_DIR/config/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;
AUTOMATIC RESTART
It is often useful for pmlogger processes (other than the primary
instance) to be started and stopped when the local host is booted or
shutdown. The script $PCP_RC_DIR/pcplocal and the necessary soft-links
are provided, and can be modified by root to run PCP tools automati‐
cally. If you want to find out more before starting, read the manual
pages for rc2(1), rc0(1), shutdown(1) and the file /etc/init.d/README.
For example, changing $PCP_RC_DIR/pcplocal so that it contains:
´start´)
# Add startup actions here
($PCP_BINADM_DIR/pmlogger_check &)
;;
´stop´)
# Add shutdown actions here
($PCP_BINADM_DIR/pmsignal -a -s TERM pmlogger &)
;;
will start pmlogger instances at boot time and terminate them in an
orderly fashion at system shutdown.
This script runs as root, so any pmlogger instances it launches are
also run as root. To run some pmlogger instances as a particular user,
create your own archive logger control file (see pmlogger_check(1)) and
use the su(1) command. e.g.
´start´)
# Add startup actions here
(su tanya -c "$PCP_BINADM_DIR/pmlogger_check -c /usr/people/tanya/ctl" &)
;;
at boot time will start the pmlogger instances described in /usr/peo‐
ple/tanya/ctl, running as user tanya.
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))
/etc/config/pmlogger
chkconfig(1M) control flag, to control launching of pmlogger
from $PCP_RC_DIR/pcp
/etc/config/pmlogger.options
command line options to pmlogger when launched from
$PCP_RC_DIR/pcp
$PCP_VAR_DIR/config/pmlogger/config.default
default configuration file for the primary logger instance
launched from $PCP_RC_DIR/pcp
$PCP_VAR_DIR/config/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 met‐
ric 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 pmlog‐
ger(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 alter‐
native 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(4).
SEE ALSOPCPIntro(1), pmcd(1), pmdumplog(1), pmlc(1), pmlogger_check(1),
pcp.conf(4), pcp.env(4) and pmns(4).
DIAGNOSTICS
The archive logs are sufficiently precious that pmlogger will not trun‐
cate 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.
Performance Co-Pilot SGI PMLOGGER(1)
