LOGARCHIVE(5) — Linux manual page

NAME | DESCRIPTION | COMMON FEATURES | ARCHIVE VOLUME (.0, .1, ...) RECORDS | METADATA FILE (.meta) RECORDS | INDEX FILE (.index) RECORDS | FILES | SEE ALSO | COLOPHON

LOGARCHIVE(5)              File Formats Manual             LOGARCHIVE(5)

NAME         top

       LOGARCHIVE - Performance Co-Pilot archive formats

DESCRIPTION         top

       Performance Co-Pilot (PCP) archives store historical values about
       arbitrary metrics recorded from a single host.  Archives are
       machine independent and self-contained - all metric data and
       metadata required for off-line or off-site analysis is held
       within an archive.

       The format is stable in order to allow long-term historical
       storage and processing by PMAPI(3) client tools.  However some
       format variants are supported over time, and currently Versions 2
       and 3 are supported.  The mandate is that PCP will provide long-
       term backwards compatibility, so an archive created on any
       version of PCP can be read on that version of PCP and all
       subsequent versions of PCP.  The exception is Version 1 that was
       retired in the PCP Version 2.0 release in May 1998.

       Archives may be read by most PCP client tools, using the
       -a/--archive NAME option, or dumped raw by pmlogdump(1).
       Archives are created primarily by pmlogger(1), however they can
       also be created using the LOGIMPORT(3) programming interface.

       Archives may be merged, analyzed, modified and subsampled using
       pmlogreduce(1), pmlogsummary(1), pmlogrewrite(1) and
       pmlogextract(1).  In addition, PCP archives may be examined in
       sets or grouped together into ``archive folios'', which are
       created and managed by the mkaf(1) and pmafm(1) tools.

       An archive consists of several physical files that share a common
       arbitrary prefix, e.g.  myarchive.

       myarchive.0, myarchive.1, ...
              One or more data volumes containing the metric values and
              any error codes encountered during metric sampling.
              Typically the largest of the files and may grow very
              rapidly, depending on the selection of metrics to be
              logged by pmlogger(1) and the sampling intervals being
              used.

       myarchive.meta
              Information for PMAPI functions such as pmLookupName(3),
              pmLookupDesc(3), pmLookupLabels(3) and pmLookupInDom(3).
              The metadata file may grow sporadically as logged metrics,
              instance domains and labels vary over time.

       myarchive.index
              A temporal index, mapping timestamps to byte offsets in
              the other files.

COMMON FEATURES         top

       All three types of files have a similar record-based structure, a
       convention of network byte-order (big-endian) encoding, and
       32-bit fields for tagging/padding for those records.  Strings are
       stored as 8-bit characters without assuming a specific encoding,
       so normally ASCII.  See also the __pmLog* types in
       src/include/pcp/libpcp.h.

   RECORD FRAMING
       The volume and .meta files are divided into self-identifying
       records.
       ┌────────┬────────┬─────────────────────────────────────────────┐
       │ Offset │ Length │                    Name                     │
       ├────────┼────────┼─────────────────────────────────────────────┤
       │      0 │      4 │ N, length of record, in bytes, including    │
       │        │        │ this field                                  │
       │      4 │    N-8 │ record payload, usually starting with a     │
       │        │        │ 32-bit record type tag                      │
       │    N-4 │      4 │ N, length of record (again)                 │
       └────────┴────────┴─────────────────────────────────────────────┘

   ARCHIVE LABEL
       All three types of files begin with an ``archive label'' header,
       which identifies the host name, starting timestamp and timezone
       information; all referring to the host that was the source of the
       performance data (which may be different to the host where
       pmlogger(1) was running).

       The ``archive label'' format differs between Version 2 and
       Version 3, with the latter providing enhanced timestamps (64-bit
       encoding of the seconds part and nanosecond precision) and some
       additional fields.

       ┌────────────────────────────────────────────────────────────────┐
       │                           Version 2                            │
       ├────────┬────────┬──────────────────────────────────────────────┤
       │ Offset │ Length │                     Name                     │
       ├────────┼────────┼──────────────────────────────────────────────┤
       │      0 │      4 │ tag, PM_LOG_MAGIC | PM_LOG_VERS02=0x50052602 │
       │      4 │      4 │ process id (PID) of pmlogger process that    │
       │        │        │ wrote file                                   │
       │      8 │      4 │ archive start time, seconds part (past UNIX  │
       │        │        │ epoch)                                       │
       │     12 │      4 │ archive start time, microseconds part        │
       │     16 │      4 │ current archive volume number (or -1=.meta,  │
       │        │        │ -2=.index)                                   │
       │     20 │     64 │ name of collection host                      │
       │     80 │     40 │ time zone string for collection host ($TZ    │
       │        │        │ environment variable)                        │
       └────────┴────────┴──────────────────────────────────────────────┘

       ┌────────────────────────────────────────────────────────────────┐
       │                           Version 3                            │
       ├────────┬────────┬──────────────────────────────────────────────┤
       │ Offset │ Length │                     Name                     │
       ├────────┼────────┼──────────────────────────────────────────────┤
       │      0 │      4 │ tag, PM_LOG_MAGIC | PM_LOG_VERS03=0x50052603 │
       │      4 │      4 │ PID of pmlogger process that wrote file      │
       │      8 │      8 │ archive start time, seconds part (past UNIX  │
       │        │        │ epoch)                                       │
       │     16 │      4 │ archive start time, nanoseconds part         │
       │     20 │      4 │ current archive volume number (or -1=.meta,  │
       │        │        │ -2=.index)                                   │
       │     24 │      4 │ archive feature bits                         │
       │     28 │      4 │ reserved for future use                      │
       │     32 │    256 │ name of collection host                      │
       │    288 │    256 │ timezone string for collection host ($TZ     │
       │        │        │ environment variable), e.g. AEDT-11          │
       │    544 │    256 │ timezone zoneinfo string for collection      │
       │        │        │ host, e.g. :Australia/Melbourne              │
       └────────┴────────┴──────────────────────────────────────────────┘

       The ``archive feature bits'' are intended to encode possible
       future extensions or differences to the on-disk structure or the
       the archive semantics.  At this stage there are no such features,
       but if they are introduced at some point in the future, there
       will be associated PM_LOG_FEATURE_XXX macros added to the
       <pcp/pmapi.h> header file.

       All fields, except for the ``current archive volume number'',
       match for all files in a single PCP archive.

ARCHIVE VOLUME (.0, .1, ...) RECORDS         top

   pmResult
       After the archive label record, an archive volume file contains
       one or more records, each providing metric values corresponding
       to the pmResult from one pmFetch(3) operation.  The record size
       may vary according to number of metrics being fetched and the
       number of instances in the associated instance domains.

       For Version 2 the file size is limited to 2GiB, due to storage of
       32-bit byte offsets within the temporal index.  For Version 3 the
       file size is limited to 8191PiB, due to storage of 62-bit byte
       offsets within the temporal index.

       The pmResult format differs between Version 2 and Version 3, with
       the latter providing enhanced timestamps (64-bit encoding of the
       seconds part and nanosecond precision).

       ┌──────────────────────────────────────────────────────────────┐
       │                          Version 2                           │
       ├─────────┬────────┬───────────────────────────────────────────┤
       │ Offset  │ Length │                   Name                    │
       ├─────────┼────────┼───────────────────────────────────────────┤
       │       0 │      4 │ timestamp, seconds part (past UNIX epoch) │
       │       4 │      4 │ timestamp, microseconds part              │
       │       8 │      4 │ number of metrics with data following     │
       │      12 │      M │ pmValueSet #0                             │
       │    12+M │      N │ pmValueSet #1                             │
       │  12+M+N │    ... │ ...                                       │
       │     NOP │      X │ pmValueBlock #0                           │
       │   NOP+X │      Y │ pmValueBlock #1                           │
       │ NOP+X+Y │    ... │ ...                                       │
       └─────────┴────────┴───────────────────────────────────────────┘

       ┌──────────────────────────────────────────────────────────────┐
       │                          Version 3                           │
       ├─────────┬────────┬───────────────────────────────────────────┤
       │ Offset  │ Length │                   Name                    │
       ├─────────┼────────┼───────────────────────────────────────────┤
       │       0 │      8 │ timestamp, seconds part (past UNIX epoch) │
       │       8 │      4 │ timestamp, nanoseconds part               │
       │      12 │      4 │ number of metrics with data following     │
       │      16 │      M │ pmValueSet #0                             │
       │    16+M │      N │ pmValueSet #1                             │
       │  16+M+N │    ... │ ...                                       │
       │     NOP │      X │ pmValueBlock #0                           │
       │   NOP+X │      Y │ pmValueBlock #1                           │
       │ NOP+X+Y │    ... │ ...                                       │
       └─────────┴────────┴───────────────────────────────────────────┘

       Records with a ``number of metrics'' equal to zero are ``mark
       records'', and represent interruptions, missing data, or time
       discontinuities in logging.

   pmValueSet
       This subrecord represents the values for one metric at one point
       in time.
     ┌────────┬────────┬────────────────────────────────────────────────┐
     │ Offset │ Length │                      Name                      │
     ├────────┼────────┼────────────────────────────────────────────────┤
     │      0 │      4 │ Performance Metrics Identifier (PMID)          │
     │      4 │      4 │ number of values                               │
     │      8 │      4 │ value format, PM_VAL_INSITU=0 or PM_VAL_DPTR=1 │
     │     12 │      M │ pmValue #0                                     │
     │   12+M │      N │ pmValue #1                                     │
     │ 12+M+N │    ... │ ...                                            │
     └────────┴────────┴────────────────────────────────────────────────┘

       The metadata describing metrics is found in the .meta file where
       the entries are not timestamped, as the metadata is assumed to be
       unchanging throughout an archive.

   pmValue
       This subrecord represents one value for one instance of a metric
       at one point in time.  It is a variant type, depending on the
       parent pmValueSet's value format field.  This allows small
       numbers to be encoded compactly, but retain flexibility for
       larger or variable length data to be stored later in the pmResult
       record in a pmValueBlock subrecord.
       ┌────────┬────────┬───────────────────────────────────────────────┐
       │ Offset │ Length │                     Name                      │
       ├────────┼────────┼───────────────────────────────────────────────┤
       │      0 │      4 │ internal instance identifier (or              │
       │        │        │ PM_IN_NULL=-1 for singular metrics)           │
       │      4 │      4 │ value (INSITU) or                             │
       │        │        │ offset in pmResult to our pmValueBlock (DPTR) │
       └────────┴────────┴───────────────────────────────────────────────┘

       The metadata describing the instance domain for metrics is found
       in the .meta file.  Since the numeric mappings may change during
       the lifetime of the logging session, it is important to match up
       the timestamp of the measurement record with the corresponding
       instance domain record.  That is, the instance domain
       corresponding to a measurement at time T is the instance domain
       observation for the metric's instance domain with largest
       timestamp T' <= T.

   pmValueBlock
       Instances of this subrecord are placed at the end of the
       pmValueSet, after all the pmValue subrecords.  If (and only if)
       needed, they are padded at the end to the next 32-bit boundary.
     ┌────────┬────────┬────────────────────────────────────────────────┐
     │ Offset │ Length │                      Name                      │
     ├────────┼────────┼────────────────────────────────────────────────┤
     │      0 │      1 │ value type (same as pmDesc.type)               │
     │      1 │      3 │ 4 + N, the length of the subrecord             │
     │      4 │      N │ bytes that make up the raw value               │
     │    4+N │    0-3 │ padding (not included in the 4+N length field) │
     └────────┴────────┴────────────────────────────────────────────────┘

       Note that for PM_TYPE_STRING, the length includes an explicit
       NULL terminator byte.  For PM_TYPE_EVENT, the value byte string
       is further structured.  Refer to PMDAEVENTARRAY(3) for more
       information about how arrays of event records are packed inside a
       pmResult container.

METADATA FILE (.meta) RECORDS         top

       After the archive label record, the metadata file contains
       interleaved metric description records, timestamped instance
       domain records, timestamped label records (for context, instance
       domain and metric labels) and (help) text records.  Unlike the
       data volumes, these records are not forced to 32-bit alignment.

       For Version 2 the file size is limited to 2GiB, due to storage of
       32-bit byte offsets within the temporal index.  For Version 3 the
       file size is limited to 8191PiB, due to storage of 62-bit byte
       offsets within the temporal index.

       See also libpcp/src/logmeta.c.

   Metric Descriptions
       Instances of this (pmDesc) record provide the description or
       metadata for each metric appearing in the PCP archive.  This
       metadata includes the metric's PMID, data type, data semantics,
       instance domain identifier (or PM_INDOM_NULL for singular metrics
       with only one value) and a set of (1 or more) names.
    ┌────────┬────────┬───────────────────────────────────────────────────┐
    │ Offset │ Length │                       Name                        │
    ├────────┼────────┼───────────────────────────────────────────────────┤
    │      0 │      4 │ tag, TYPE_DESC=1                                  │
    │      4 │      4 │ PMID                                              │
    │      8 │      4 │ data type (PM_TYPE_*)                             │
    │     12 │      4 │ instance domain identifier                        │
    │     16 │      4 │ metric semantics (PM_SEM_*)                       │
    │     20 │      4 │ units: bit-packed pmUnits                         │
    │      4 │      4 │ number of alternative names for this PMID         │
    │     28 │      4 │ N: number of bytes in this name                   │
    │     32 │      N │ bytes of the name, no NULL terminator nor padding │
    │   32+N │      4 │ N2: number of bytes in next name                  │
    │   36+N │     N2 │ bytes of the name, no NULL terminator nor padding │
    │    ... │    ... │ ...                                               │
    └────────┴────────┴───────────────────────────────────────────────────┘

   Instance Domains
       A set-valued metric is defined over an instance domain, which
       consists of an instance domain identifier (will have already been
       mentioned in a prior pmDesc record), a count of the number of
       instances and a map that defines the association between internal
       instance identifiers (integers) and external instance names
       (strings).

       Because instance domains can change over time, the instance
       domain also requires a timestamp, and the same instance domain
       can occur multiple times within the .meta file.  The timestamps
       are used to search for the temporally correct instance domain
       when decoding pmResult records from the archive data volumes, or
       answering metadata queries against the instance domain.

       The instance domain format differs markedly between Version 2 and
       Version 3.  Version 3 provides enhanced timestamps (64-bit
       encoding of the seconds part and nanosecond precision) and
       introduces a new ``delta'' instance domain format that encodes
       differences between the previous observation of the instance
       domain and the current state of the instance domain.

     ┌───────────────────────────────────────────────────────────────────┐
     │                 Full Instance Domain - Version 2                  │
     ├──────────┬────────┬───────────────────────────────────────────────┤
     │  Offset  │ Length │                     Name                      │
     ├──────────┼────────┼───────────────────────────────────────────────┤
     │        0 │      4 │ tag, TYPE_INDOM_V2=2                          │
     │        4 │      4 │ timestamp, seconds part (past UNIX epoch)     │
     │        8 │      4 │ timestamp, microseconds part                  │
     │       12 │      4 │ instance domain number                        │
     │       16 │      4 │ N: number of instances in domain, normally >0 │
     │       20 │      4 │ first instance number                         │
     │       24 │      4 │ second instance number (if appropriate)       │
     │      ... │    ... │ ...                                           │
     │   20+4*N │      4 │ first offset into string table (see below)    │
     │ 20+4*N+4 │      4 │ second offset into string table (etc.)        │
     │      ... │    ... │ ...                                           │
     │   20+8*N │      M │ base of string table, containing              │
     │          │        │ packed, NULL-terminated instance names        │
     └──────────┴────────┴───────────────────────────────────────────────┘

     ┌───────────────────────────────────────────────────────────────────┐
     │                 Full Instance Domain - Version 3                  │
     ├──────────┬────────┬───────────────────────────────────────────────┤
     │  Offset  │ Length │                     Name                      │
     ├──────────┼────────┼───────────────────────────────────────────────┤
     │        0 │      4 │ tag, TYPE_INDOM=5                             │
     │        4 │      8 │ timestamp, seconds part (past UNIX epoch)     │
     │       12 │      4 │ timestamp, nanoseconds part                   │
     │       16 │      4 │ instance domain number                        │
     │       20 │      4 │ N: number of instances in domain, normally >0 │
     │       24 │      4 │ first instance number                         │
     │       28 │      4 │ second instance number (if appropriate)       │
     │      ... │    ... │ ...                                           │
     │   24+4*N │      4 │ first offset into string table (see below)    │
     │ 24+4*N+4 │      4 │ second offset into string table (etc.)        │
     │      ... │    ... │ ...                                           │
     │   24+8*N │      M │ base of string table, containing              │
     │          │        │ packed, NULL-terminated instance names        │
     └──────────┴────────┴───────────────────────────────────────────────┘

       The ``delta'' instance domain record in Version 3 uses the same
       physical structure as the ``full'' instance domain above with the
       following differences:
       *  The tag is TYPE_INDOM_DELTA=6.
       *  The ``number of instances in domain'' field becomes the sum of
          the number of instances added and the number of instances
          deleted.
       *  Deleted instances are encoded with the string offset set to -1
          and there is no corresponding string table entry.
       *  Added instances are encoded exactly the same way.

       The ``delta'' instance domain format is used to provide a more
       compact on-disk encoding for instance domains that have a large
       number of instances and are subject to frequent small changes,
       e.g. the instance domain of process ids, as exported by
       pmdaproc(1).

       For ``full'' instance domain records the instance domain replace
       the previous instance domain: prior records are not searched for
       instance domain metadata queries after this timestamp.

       Each instance domain in a Version 3 archive must have an initial
       ``full'' instance domain record.  Subsequent records for the same
       instance domain can be the `full'' or the ``delta'' variant.  Any
       instance mentioned in the prior observation of an instance domain
       that is not mentioned in the ``delta'' instance domain record is
       assumed to continue to exist for the current observation of the
       instance domain.

   Labels for Contexts, Instance Domains and Metrics
       Instances of this (pmLogLabelSet) record provide sets of label-
       name:label-value pairs associated with labels of the context,
       instance domains and individual performance metrics - refer to
       pmLookupLabels(3) for further details.

       Any instance domain identifier will have already been mentioned
       in a prior pmDesc record.

       As new labels can appear during an archiving session, these
       records are timestamped and must be searched when decoding
       pmResult records from the archive data volumes.  The
       pmLogLabelSet format differs between Version 2 and Version 3,
       with the latter providing enhanced timestamps (64-bit encoding of
       the seconds part and nanosecond precision).

    ┌───────────────────────────────────────────────────────────────────────┐
    │                               Version 2                               │
    ├─────────────┬────────┬────────────────────────────────────────────────┤
    │   Offset    │ Length │                      Name                      │
    ├─────────────┼────────┼────────────────────────────────────────────────┤
    │           0 │      4 │ tag, TYPE_LABEL_V2=3                           │
    │           4 │      4 │ timestamp, seconds part (past UNIX epoch)      │
    │           8 │      4 │ timestamp, microseconds part                   │
    │          12 │      4 │ label type (PM_LABEL_* type macros.)           │
    │          16 │      4 │ numeric identifier - domain, PMID, etc or      │
    │             │        │ PM_IN_NULL=-1 for context labels               │
    │          20 │      4 │ N: number of label sets in this record,        │
    │             │        │ usually 1 except in the case of instances      │
    │          24 │      4 │ offset to the start of the JSONB labels string │
    │          28 │     L1 │ first labelset array entry (see below)         │
    │         ... │    ... │ ...                                            │
    │       28+L1 │     LN │ N-th labelset array entry (see below)          │
    │         ... │    ... │ ...                                            │
    │ 28+L1+...LN │      M │ concatenated JSONB strings for all labelsets   │
    └─────────────┴────────┴────────────────────────────────────────────────┘

    ┌───────────────────────────────────────────────────────────────────────┐
    │                               Version 3                               │
    ├─────────────┬────────┬────────────────────────────────────────────────┤
    │   Offset    │ Length │                      Name                      │
    ├─────────────┼────────┼────────────────────────────────────────────────┤
    │           0 │      4 │ tag, TYPE_LABEL=7                              │
    │           4 │      8 │ timestamp, seconds part (past UNIX epoch)      │
    │          12 │      4 │ timestamp, nanoseconds part                    │
    │          16 │      4 │ label type (PM_LABEL_* type macros.)           │
    │          20 │      4 │ numeric identifier - domain, PMID, etc or      │
    │             │        │ PM_IN_NULL=-1 for context labels               │
    │          24 │      4 │ N: number of label sets in this record,        │
    │             │        │ usually 1 except in the case of instances      │
    │          28 │      4 │ offset to the start of the JSONB labels string │
    │          32 │     L1 │ first labelset array entry (see below)         │
    │         ... │    ... │ ...                                            │
    │       32+L1 │     LN │ N-th labelset array entry (see below)          │
    │         ... │    ... │ ...                                            │
    │ 32+L1+...LN │      M │ concatenated JSONB strings for all labelsets   │
    └─────────────┴────────┴────────────────────────────────────────────────┘

       Records of this form replace the existing labels for a given
       label type: prior records are not searched for resolving that
       class of label in measurements after this timestamp.

       The individual labelset array entries are variable length,
       depending on the number of labels present within that set.  These
       entries contain the instance identifiers (in the case of type
       PM_LABEL_INSTANCES labels), lengths and offsets of each label
       name and value, and also any flags set for each label.
       ┌────────┬────────┬───────────────────────────────────────────┐
       │ Offset │ Length │                   Name                    │
       ├────────┼────────┼───────────────────────────────────────────┤
       │      0 │      4 │ instance identifier (or PM_IN_NULL=-1)    │
       │      4 │      4 │ length of JSONB label string              │
       │      8 │      4 │ N: number of labels in this labelset      │
       │     12 │      2 │ first label name offset                   │
       │     14 │      1 │ first label name length                   │
       │     15 │      1 │ first label flags (e.g. optionality)      │
       │     16 │      2 │ first label value offset                  │
       │     18 │      2 │ first label value length                  │
       │     20 │      2 │ second label name offset (if appropriate) │
       │    ... │    ... │ ...                                       │
       └────────┴────────┴───────────────────────────────────────────┘

   Help Text
       This (pmLogText) record stores help text associated with a metric
       or an instance domain - as provided by pmLookupText(3) and
       pmLookupInDomText(3).

       The metric identifier and instance domain identifier will have
       already been mentioned in a prior pmDesc record.

      ┌────────┬────────┬──────────────────────────────────────────────┐
      │ Offset │ Length │                     Name                     │
      ├────────┼────────┼──────────────────────────────────────────────┤
      │      0 │      4 │ tag, TYPE_TEXT=4                             │
      │      4 │      4 │ text and identifier type (PM_TEXT_* macros.) │
      │      8 │      4 │ numeric identifier - PMID or instance domain │
      │     12 │      M │ help text string, arbitrary text             │
      └────────┴────────┴──────────────────────────────────────────────┘

INDEX FILE (.index) RECORDS         top

       After the archive label record, the temporal index file contains
       a plainly concatenated, unframed group of tuples, which relate
       timestamps to the byte offsets in the volume and .meta files.
       These records are fixed size, fixed format, and are not enclosed
       in the standard length/payload/length wrapper: they take up the
       entire remainder of the .index file after the archive label
       record.

       The temporal index file provides a rapid way of seeking to a
       particular point of time within an archive for both the
       performance metric values and the associated metadata.

       See also libpcp/src/logutil.c.

       The index format differs between Version 2 and Version 3, with
       the latter providing enhanced timestamps (64-bit encoding of the
       seconds part and nanosecond precision) and 64-bit byte offsets.

       ┌─────────────────────────────────────────────────────────────┐
       │                          Version 2                          │
       ├────────┬────────┬───────────────────────────────────────────┤
       │ Offset │ Length │                   Name                    │
       ├────────┼────────┼───────────────────────────────────────────┤
       │      0 │      4 │ timestamp, seconds part (past UNIX epoch) │
       │      4 │      4 │ timestamp, microseconds part              │
       │      8 │      4 │ archive volume number (0...N)             │
       │     12 │      4 │ byte offset in .meta file                 │
       │     16 │      4 │ byte offset in archive volume file        │
       └────────┴────────┴───────────────────────────────────────────┘

       ┌─────────────────────────────────────────────────────────────┐
       │                          Version 3                          │
       ├────────┬────────┬───────────────────────────────────────────┤
       │ Offset │ Length │                   Name                    │
       ├────────┼────────┼───────────────────────────────────────────┤
       │      0 │      8 │ timestamp, seconds part (past UNIX epoch) │
       │      8 │      4 │ timestamp, nanoseconds part               │
       │     12 │      4 │ archive volume number (0...N)             │
       │     16 │      8 │ byte offset in .meta file                 │
       │     24 │      8 │ byte offset in archive volume file        │
       └────────┴────────┴───────────────────────────────────────────┘

       Since the temporal index is optional, and exists only to speed up
       time-based random access to metrics and their metadata, the index
       records are emitted only intermittently.  An archive reader
       program should not presume any particular rate of data flow into
       the index.  However, common events that may trigger a new
       temporal index record include changes in instance domains,
       switching over to a new archive volume, and starting or stopping
       logging.  One reliable invariant however is that, for each index
       entry, there are to be no meta or archive volume records with a
       timestamp after that in the index, but physically before the
       associated byte offset in the index.

FILES         top

       Several PCP tools create archives in standard locations:

       $HOME/.pcp/pmlogger
              default location for the interactive chart recording mode
              in pmchart(1)
       $PCP_LOG_DIR/pmlogger
              default location for pmlogger_daily(1) and
              pmlogger_check(1) scripts

SEE ALSO         top

       mkaf(1), PCPIntro(1), pmafm(1), pmchart(1), pmdaproc(1),
       pmlogdump(1), pmlogger(1), pmlogger_check(1), pmlogger_daily(1),
       pmlogreduce(1), pmlogrewrite(1), pmlogsummary(1), LOGIMPORT(3),
       PMAPI(3), pmLookupDesc(3), pmLookupInDom(3),
       pmLookupInDomText(3), pmLookupLabels(3), pmLookupName(3),
       pmLookupText(3), pcp.conf(5) and pcp.env(5).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at 
       ⟨http://www.pcp.io/⟩.  If you have a bug report for this manual
       page, send it to [email protected].  This page was obtained from the
       project's upstream Git repository
       ⟨https://github.com/performancecopilot/pcp.git⟩ on 2024-06-14.
       (At that time, the date of the most recent commit that was found
       in the repository was 2024-06-14.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       [email protected]

Performance Co-Pilot                                       LOGARCHIVE(5)

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