Munin contributed plugins

#!/usr/bin/perl -w

=head1 NAME

btrfs_subvol_usage - Plugin to monitor usage of BTRFS subvolumes

=head1 CONFIGURATION

Must be run as root and you have to specify the path to the filesystem

 [btrfs_usage]

 user root

 env.fsroot /path/to/btrfs/filesystem

=head1 MAGIC MARKERS

 #%# family=auto

 #%# capabilities=autoconf

=head1 USAGE

Link/Copy this plugin to /etc/munin/plugins/ and restart the munin-node.

=head1 AUTHOR

Alexander Knöbel <alex@belogy.de>

=head1 LICENSE

GPLv2

=cut

use strict;

use Munin::Plugin;

if ($ARGV[0] and $ARGV[0] eq 'autoconf') {

	if (-e "/sbin/btrfs") {

		print "yes\n";

	} else {

		print "no (/sbin/btrfs is missing)\n";

	}

	exit 0;

}

my @fsroot;

if ( !defined( $ENV{"fsroot"} ) ) {

	die "No fsroot given! See the manual at top of this plugin file.";

}

@fsroot = $ENV{"fsroot"};

# get subvolumes

my %subvols;

open(SVS, "btrfs subvolume list --sort=path @fsroot |")

	or die("Failed to run 'btrfs subvolume list': " . $!);

while (my $line = <SVS>) {

	chomp $line;

	$line =~ s/ID ([0-9]+) gen ([0-9]+) top level ([0-9]+) path (.+)//;

	$subvols{$1}->{id} = $1;

	$subvols{$1}->{name} = $4;

}

close SVS;

# get sizes from quota

open(QGS, "btrfs qgroup show --raw @fsroot |")

	or die("Failed to run 'btrfs qgroup show': " . $!);

while (my $line = <QGS>) {

	chomp $line;

	$line =~ s|([0-9]+)/([0-9]+)\s+([0-9]+)\s+([0-9]+)||;

	if (defined($2) && defined($subvols{$2})) {

		$subvols{$2}->{rfer} = $3;

		$subvols{$2}->{excl} = $4;

	}

}

close QGS;

# print config

if ($ARGV[0] and $ARGV[0] eq 'config') {

	print "btrfs_usage\n";

	print "graph_title BTRFS Subvolume usage\n";

	print "graph_args --base 1024 --lower-limit 0\n";

	print "graph_vlabel Bytes\n";

	print "graph_category disk\n";

	for my $id (sort { $subvols{$a}->{name} cmp $subvols{$b}->{name} } keys %subvols) {

		print "$id.label " . $subvols{$id}->{name} . "\n";

		print "$id.type GAUGE\n";

		print "$id.draw LINE2\n";

	}

	exit 0;

}

# print usage

print "btrfs_subvol_usage\n";

for my $id (sort { $subvols{$a}->{name} cmp $subvols{$b}->{name} } keys %subvols) {

	print "$id.value " . $subvols{$id}->{rfer} . "\n";

}