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.

Performance Co-Pilot                                   PCP                                         PMLOGCHECK(1)