Ubuntu Manpage: pmlogcheck - checks for invalid data in a PCP archive

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).

DIAGNOSTICS

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