sampler-file-server.yml

A basic sampler dashboard definition for monitoring a file server on a terminal.

Special requirements:

• btrbk, configured to take snapshots
• sampler
• sar systat (only the sar executable is required, it is safe to disable the sysstat service after installation)

The configuration file defines a 80 columns x 40 rows basic console dashboard for a file server that uses a btrfs volume for the data served, and btrbk to orchestrate a snapshotting process. To configure the dashboard, adjust the variables at the top of the script.

How to display the dashboard, after logging in to the backup server:

sampler --config sampler-file-server.yml

You’ll most likely want to use its sister script sampler-backup-server.yml, on the backup server.

variables:
    # Configure these:
    btrbk_config: "/etc/btrbk-snapshot.conf"
    mountpoint_data: "/data"
    network_interface: "eno1"
    tmp_dir: "/tmp"
    max_data_usage_percent: 80 # before visual alert
    max_root_usage_percent: 66 # before visual alert

# Positions within 80x40 grid
# Colors: https://www.ditig.com/256-colors-cheat-sheet
textboxes:
  - title: "Latest snapshots"
    position: [[0, 15], [80, 23]]
    rate-ms: 60000
    sample: btrbk -c $btrbk_config --format=table list latest

  - title: systemdummy # never displayed, just for collecting data
    position: [[1000, 1000], [0, 0]]
    rate-ms: 983
    sample: LC_ALL= LC_TIME="en_DK" sar 1 1 -u ALL | tail -n 1 | tee "$tmp_dir/sarsys.tmp"

  - title: networkdummy # never displayed, just for collecting data
    position: [[1000, 1000], [0, 0]]
    rate-ms: 983
    sample: LC_ALL= LC_TIME="en_DK" sar 1 1 -n DEV --iface=$network_interface | tail -n 1 | tee "$tmp_dir/sarnet.tmp"

gauges:
  - title: "Data space used % (MB)"
    position: [[0, 0], [40, 3]]
    rate-ms: 5000
    scale: 2
    percent-only: false
    color: 220
    # variables unavailable in trigger conditions, workaround via name pipe
    init: mkfifo datavolume
    cur:
      sample: df --block-size=1000000 --output=used $mountpoint_data | sed -e 1d -e 's/[^0-9]//g'
    max:
      sample: df --block-size=1000000 --output=size $mountpoint_data | sed -e 1d -e 's/[^0-9]//g'
    min:
      sample: echo "$max_data_usage_percent $mountpoint_data" > datavolume && echo 0
    triggers:
      - title: "Data FS running out of space"
        # Pull mountpoint and max usage from named pipe, since variables are unsupported in conditions
        condition: DATA=$(cat < datavolume) && DATAMOUNT=$(echo $DATA | cut -f2- -d' ') && DATAUSAGE=$(echo $DATA | cut -f1 -d' ') && echo "$(df --block-size=1000000 --output=used ${DATAMOUNT} | sed -e 1d -e 's/[^0-9]//g') * 100 / $(df --block-size=1000000 --output=size ${DATAMOUNT} | sed -e 1d -e 's/[^0-9]//g') >= $DATAUSAGE" | bc -l
        actions:
          visual: true

  - title: "RAM unavailable kB"
    position: [[40, 0], [40, 3]]
    rate-ms: 2000
    scale: 2
    percent-only: false
    color: 220
    cur:
      sample: awk '/MemAvailable/{available=$2} /MemTotal/{total=$2} END{print (total-available)}' /proc/meminfo
    max:
      sample: awk '/MemTotal/{total=$2} END{print (total)}' /proc/meminfo   # sample script for max value
    min:
      sample: echo 0

  - title: "/ root space used % (MB)"
    position: [[0, 38], [40, 3]]
    rate-ms: 5000
    scale: 2
    percent-only: false
    color: 220
    # variables unavailable in trigger conditions, workaround via name pipe
    init: mkfifo rootusage
    cur:
      sample: df --block-size=1000000 --output=used / | sed -e 1d -e 's/[^0-9]//g'
    max:
      sample: df --block-size=1000000 --output=size / | sed -e 1d -e 's/[^0-9]//g'
    min:
      sample: echo $max_root_usage_percent > rootusage && echo 0
    triggers:
      - title: "/ running out of space"
        condition: ROOTUSAGE=$(cat < rootusage) && echo "$(df --block-size=1000000 --output=used / | sed -e 1d -e 's/[^0-9]//g') * 100 / $(df --block-size=1000000 --output=size / | sed -e 1d -e 's/[^0-9]//g') >= $ROOTUSAGE" | bc -l
        actions:
          visual: true

runcharts:
  - title: "Network interface kB/s"
    position: [[0, 3], [40, 12]]
    rate-ms: 997 # slight offset to dummy data collector
    scale: 0
    legend:
      enabled: true
      details: true
    items:
      - label: "rxkB/s"
        color: 111
        sample: awk '{print $5}' "$tmp_dir/sarnet.tmp"
      - label: "txkB/s"
        color: 220
        sample: awk '{print $6}' "$tmp_dir/sarnet.tmp"

  - title: "System activity %"
    position: [[40, 3], [40, 12]]
    rate-ms: 997 # slight offset to dummy data collector
    scale: 0
    legend:
      enabled: true
      details: true
    items:
      - label: "%idle"
        color: 254
        sample: awk '/all/{print $12}' "$tmp_dir/sarsys.tmp"
      - label: "%iowait"
        color: 160
        sample: awk '/all/{print $6}' "$tmp_dir/sarsys.tmp"
      - label: "%usr"
        color: 220
        sample: awk '/all/{print $3}' "$tmp_dir/sarsys.tmp"
      - label: "%sys"
        color: 70
        sample: awk '/all/{print $5}' "$tmp_dir/sarsys.tmp"
      - label: "%ifutil"
        color: 111
        sample: awk '{print $10}' "$tmp_dir/sarnet.tmp"

Image Credits:
Papirus icon for Terminal (modified) | GNU General Public License, version 3▫ Basic sampler dashboard for a backup server | by Rolf F. Katzenberger | Licensed under Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)

Licensing:
This content is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
For your attributions to us please use the word »tuxwise«, and the link https://tuxwise.net.