pmlogcheck(1)

NAME

   pmlogcheck - checks for invalid data in a PCP archive

SYNOPSIS

   pmlogcheck  [-lz]  [-n  pmnsfile]  [-S start] [-T finish] [-Z timezone]
   archive

DESCRIPTION

   pmlogcheck prints information about the  nature  of  any  invalid  data
   which it detects in the files of a PCP archive.

   The  archive  has  the  base name archive and must have been previously
   created using pmlogger(1).

   Normally pmlogcheck operates on the default  Performance  Metrics  Name
   Space  (pmns(5)),  however if the -n option is specified an alternative
   namespace is loaded from the file pmnsfile.

   The command line options -S and -T can be used to specify a time window
   over  which  metrics  should  be  checked in Pass 3 (see below).  These
   options are common to many Performance Co-Pilot  tools  and  are  fully
   described in PCPIntro(1).

   The -l option prints the archive label, showing the log format version,
   the time and date for the start and (current) end of the  archive,  and
   the host from which the performance metrics values were collected.

   By  default,  pmlogcheck reports the time of day according to the local
   timezone on the system where pmlogcheck is run.  The -Z option  changes
   the  timezone  to timezone in the format of the environment variable TZ
   as described in environ(7).  The -z option changes the timezone to  the
   local  timezone  at  the  host  that  is  the source of the performance
   metrics, as specified in the label record of the archive log.

   The checking proceeds in a number of passes, each designed to  validate
   progressively   more   complex   semantic   relationships  between  the
   information in a PCP archive.

Pass 0

   Each physical file of the PCP archive is processed to ensure the  label
   records  are  valid  and  consistent,  and  that  each file contains an
   integral number of physical records with  correct  header  and  trailer
   fields.

   Any  errors  at  this  stage  are  usually  fatal.   The PCP archive is
   probably damaged beyond repair, and no more passes  of  pmlogcheck  are
   attempted.

Pass 1

   Validates the integrity of the temporal index, usually archive.index.

   As  the  temporal index is (strictly speaking) optional, errors at this
   stage are handled by marking the index as bad and ignoring it  for  the
   remainder of the pmlogcheck passes.

   Permanent  repair  can  be achieved by removing the temporal index file
   and then making a copy of the  PCP  archive  using  pmlogrewrite(1)  or
   pmlogextract(1).   This will create a new temporal index for the copied
   archive as a side-effect.

Pass 2

   Validates the integrity of the metadata file, usually archive.meta.

Pass 3

   Validates the integrity of each of the log volumes of the PCP  archive,
   usually archive.0, archive.1, etc.

   There  is  some basic integrity checks to ensure the encoding of values
   for each metric remains consistent  and  the  values  are  well  formed
   across all the observations in the archive.

   Also   the   timestamps   for  the  observations  are  expected  to  be
   monotonically increasing as the archive is tranversed.

   Additional  attention  is  given  to   counter   metrics   (type   from
   pmLookupDesc(3)   is   PM_SEM_COUNTER)   which  are  expected  to  have
   monotonically increasing values.   If  the  values  are  not  monotonic
   increasing  this  may  suggest a counter wrap has happened or there has
   been some interruption  or  reset  to  the  underlying  source  of  the
   performance data that is no captured in the archive.

   For  each  counter  metric which has been detected as having wrapped at
   some point in the archive, pmlogcheck produces  output  describing  the
   metric name (with instance identifiers where appropriate), the internal
   storage type for the metric, the value of the metric before the counter
   wrap (with its associated timestamp), and the value of the metric after
   the wrap (also with a timestamp).

   pmlogcheck produces two different timestamp formats, depending  on  the
   interval  over which it is run.  For an interval greater than 24 hours,
   the date is displayed in addition to the time at which the counter wrap
   occurred.   If  the  extent  of  the data being checked is less than 24
   hours,  a  more  precise  format  is  used  (time  is  displayed   with
   millisecond precision, but without the date).

FILES

   $PCP_VAR_DIR/pmns/*
             default PMNS specification files
   $PCP_LOG_DIR/pmlogger/hostname
             default  directory  for  PCP  archives containing performance
             data collected from the host hostname.

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),      pmdumplog(1),      pmlogextract(1),      pmlogger(1),
   pmlogrewrite(1),     pmlogsummary(1),     pmval(1),    pmLookupDesc(3),
   pcp.conf(5), pcp.env(5) and pmns(5).

DIAGNOSTICS

   All are generated on standard  error  and  are  intended  to  be  self-
   explanatory.

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