Performance Co-Pilot PMDA for Monitoring Device Mapper Stats
============================================================
This PMDA is capable of collecting statistics from Device Mapper

The PMDA collects its data through the dmsetup utility and requires that the
program is installed in order to function. 

Metrics
=======

The file ./help contains descriptions for all of the metrics which are
exposed by this PMDA.

Once the PMDA has been installed, the following command will list all of
the available metrics and their explanatory “help” text:

    + # $ pminfo -fT dm

Installation
============

    + # cd $PCP_PMDAS_DIR/dm

    + Check that there is no clash in the Performance Metrics Domain
      defined in ./domain.h and the other PMDA's currently in use (see
      $PCP_PMCDCONF_PATH). If there is, edit ./domain.h to choose another
      domain number.

    + Then simply use

        # ./Install

 	and choose both the “collector” and “monitor” installation
        configuration options.

De-Installation
===============

    + Simply use

        # cd $PCP_PMDAS_DIR/dm
        #./Remove

Troubleshooting
===============

    + After installing or restarting the agent, the PMCD log file
      ($PCP_LOG_DIR/pmcd/pmcd.log) and the PMDA log file
      ($PCP_LOG_DIR/PMCD/dm.log) should be checked for any warnings or
      errors.

    + In an event where no values are being returned for most of the
      metrics, check to ensure that there is output given for thin
      pool and thin volumes by the dmsetup utility (needs to be run
      as root). 

          $ dmsetup status --target thin-pool

          $ dmsetup status --target thin

          $ dmsetup status --target cache

