PMDABTRFS(1)                General Commands Manual               PMDABTRFS(1)

NAME
       pmdabtrfs - btrfs filesystem performance metrics domain agent (PMDA)

SYNOPSIS
       $PCP_PMDAS_DIR/btrfs/pmdabtrfs [-D debug] [-d domain] [-l logfile]

DESCRIPTION
       pmdabtrfs is a Performance Metrics Domain Agent (PMDA) which extracts
       performance metrics from the btrfs filesystem via sysfs
       (/sys/fs/btrfs).

       The btrfs PMDA exports metrics covering filesystem information (label,
       sizes, generation, checksum algorithm), transaction commit statistics,
       space allocation for data, metadata and system block groups, per-device
       error statistics, and async discard statistics.

       Metrics are organized into two instance domains: one for btrfs
       filesystems (keyed by UUID) and one for devices (keyed by UUID::devid).
       Labels are provided for each instance, including the filesystem UUID,
       label, and device ID where applicable.

       A brief description of the pmdabtrfs command line options follows:

       -d   The performance metrics domain number must be set to a unique
            value.

       -l   Location of the log file.  By default, a log file named btrfs.log
            is written in the current directory of pmcd(1) when pmdabtrfs is
            started, i.e.  $PCP_LOG_DIR/pmcd.  If the log file cannot be
            created or is not writable, output is written to the standard
            error instead.

INSTALLATION
       The btrfs PMDA requires a Linux system with one or more mounted btrfs
       filesystems.  The PMDA reads statistics from sysfs and does not require
       root privileges.

       Install the PMDA using the Install script:

            # cd $PCP_PMDAS_DIR/btrfs
            # ./Install

       To remove the PMDA use the Remove script:

            # cd $PCP_PMDAS_DIR/btrfs
            # ./Remove

DEBUGGING OPTIONS
       The -D or --debug option enables the output of additional diagnostics
       on stderr to help triage problems, although the information is
       sometimes cryptic and primarily intended to provide guidance for
       developers rather end-users.  debug is a comma separated list of
       debugging options; use pmdbg(1) with the -l option to obtain a list of
       the available debugging options and their meaning.

       Debugging options specific to pmdabtrfs are as follows:

       +-------+---------------------------------------------------+
       |Option | Description                                       |
       +-------+---------------------------------------------------+
       |appl0  | warn if the btrfs sysfs directory cannot be found |
       +-------+---------------------------------------------------+
ENVIRONMENT
       The BTRFS_PATH environment variable can be set to override the default
       sysfs path (/sys/fs/btrfs) for testing purposes.

SEE ALSO
       PCPIntro(1), pmcd(1), pcp.conf(5) and pcp.env(5).


Performance Co-Pilot                  PCP                         PMDABTRFS(1)