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   pmda    ( 3 )

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NAMESPACE

Every PMDA has its own unique namespace using the format defined in PMNS(5). In summary, the namespace matches the names of the metrics to the unique identifier. The simple PMDA defines five metrics: simple.numfetch, simple.color, simple.time.user, simple.time.sys and simple.now. The namespace for these metrics is defined in $PCP_PMDAS_DIR/simple/pmns and is installed as:

simple { numfetch 253:0:0 color 253:0:1 time now 253:2:4 }

simple.time { user 253:1:2 sys 253:1:3 }

The domain number of 253 is obtained from $PCP_VAR_DIR/pmns/stdpmid. New PMDAs should specify a unique domain number in this file, and obtain the number during installation. This allows the domain number to change by modifying only the file $PCP_VAR_DIR/pmns/stdpmid.

The simple.time and simple.now metrics are defined in separate clusters to the other metrics which allows a PMDA to support more than 1024 metrics, as well as grouping similar metrics together. Therefore, the item numbers for a new cluster may be identical to the item numbers in other clusters. The simple PMDA continues to increment the item numbers to permit direct mapping (see pmdaInit(3)).

The namespace file should be installed and removed with the agent using pmnsadd(1) and pmnsdel(1). See the later sections on INSTALLATION and REMOVAL.

A simple ASCII namespace can be constructed by creating a file similar to $PCP_PMDAS_DIR/simple/root:

/* * fake "root" for validating the local PMNS subtree */

#include "$PCP_VAR_DIR/pmns/stdpmid"

root { simple }

#include "pmns"

and can be referred to with the -n option in most PCP tools.