Munin contributed plugins

#!/bin/sh

# -*- sh -*-

set -eu

: <<=cut

=head1 NAME

zpool_iostat - Plugin to monitor transfer statistics of ZFS pools

=head1 APPLICABLE SYSTEMS

All systems with "zpool" installed.

=head1 CONFIGURATION

No configuration is required.

=head1 INTERPRETATION

This plugin shows a graph with read (positive) and write (negative) values

for the IO transfer of each pool.

=head1 MAGIC MARKERS

  #%# family=auto

  #%# capabilities=autoconf

=head1 AUTHOR

tsaavik <github@hellspark.com>

Peter Doherty <peterd@acranox.org>

Lars Kruse <devel@sumpfralle.de>

=head1 LICENSE

GPLv2

=cut

# shellcheck source=/usr/share/munin/plugins/plugin.sh

. "$MUNIN_LIBDIR/plugins/plugin.sh"

ZPOOL_BIN=/sbin/zpool

ACTION="${1:-}"

if [ "$ACTION" = "autoconf" ]; then

	if [ -x "$ZPOOL_BIN" ]; then

		echo yes

	else

		echo "no (missing executable '$ZPOOL_BIN')"

	fi

	exit 0

fi

zlines=$("$ZPOOL_BIN" iostat -v | wc -l | sed 's/ //g')

iostats=$("$ZPOOL_BIN" iostat -v 1 1 | tail "-$zlines")

zlist=$(echo "$iostats" \

	| gawk '/alloc/ {next}; /avail/ {next}; /raid/ {next}; /mirror/ {next};

		{ if ( $4 >=0 ) print $1}' \

	| tr ' ' '\n')

# Parse the n'th column of the iostat output for a given pool or disk as a

# number (interpreting K and M suffixes).

get_device_iostat_column() {

	local device_label="$1"

	local stat_column="$2"

	# convert all numeric values into kB

	echo "$iostats" \

		| gawk '{ if ($1 == "'"$device_label"'")

				print $'"$stat_column"'; }' \

		| gawk '/M/ {print strtonum($1)*1000};

			/K/ {print strtonum($1)};

			/[0-9]$/ {print int($1)/1000}'

}

get_device_fieldname() {

	local device_id="$1"

	# Backwards compatibility (until 2016): keep the unprefixed pool name

	# for the fieldname, except for pool names starting with digits.

	if echo "$device_id" | grep -q "^[0-9]"; then

		clean_fieldname "_$device_id"

	else

		clean_fieldname "$device_id"

	fi

}

if [ "$ACTION" = "config" ]; then

	echo 'graph_title zpool iostat'

	echo 'graph_args --base 1000 -l 0'

	echo 'graph_vlabel write (-) / read (+) KBytes/s'

	echo 'graph_category disk'

	echo 'graph_scale no'

	echo 'graph_info This graph shows zpool iostat'

	# Assemble the "graph_order" as a sorted list of read/write pairs for

	# each device.

	printf "graph_order"

	echo "$zlist" | while read -r device_id; do

		fieldname="$(get_device_fieldname "pool_$device_id")"

		printf " %s_read %s_write" "$fieldname" "$fieldname"

	done

	# finalize the 'graph_order' with a newline

	echo

	# output all fields: write as negative numbers and read as positive

	echo "$zlist" | while read -r device_id; do

		fieldname="$(get_device_fieldname "pool_$device_id")"

		echo "${fieldname}_read.label $device_id"

		echo "${fieldname}_read.type GAUGE"

		echo "${fieldname}_read.graph no"

		echo "${fieldname}_write.label $device_id"

		echo "${fieldname}_write.type GAUGE"

		echo "${fieldname}_write.negative ${fieldname}_read"

	done

	exit 0

fi

echo "$zlist" | while read -r device_id; do

	fieldname="$(get_device_fieldname "pool_$device_id")"

	echo "${fieldname}_read.value $(get_device_iostat_column "$device_id" 6)"

	echo "${fieldname}_write.value $(get_device_iostat_column "$device_id" 7)"

done