Chart Plotter of nfs-iostat output

Nowadays, many tools exist for graphing and monitoring and sometimes we need to build graphs from nfsiostat output file like in the good old days. By default, the nfsiostat output does not contain a time-stamp in its iterations. Therefore, an interval (in seconds) is a mandatory input for nfsioplotter.py script. There are no computations made with the timeline except using it for x-axis in the charts. The script produces four graphs (IOPS, Throughput, Request Size per operation and Average Round-Trip Time)

• NFS iostat data that looks like this:

  1.2.3.4:/pg_db_data mounted on /db/nfspostgres_data:
  
               op/s   rpc bklog
             196.86      0.00
  
  read:             ops/s      kB/s     kB/op   retrans   avg RTT (ms)  avg exe (ms)
                    8.195   414.453    50.576  0 (0.0%)          1.351         1.420
  write:            ops/s      kB/s     kB/op   retrans   avg RTT (ms)  avg exe (ms)
                   38.824   500.058    12.880  0 (0.0%           2.991        20.793
  
  1.2.3.4:/pg_db_wal mounted on /db/nfspostgres_wal:
  
               op/s   rpc bklog
             196.80      0.00
  
  read:             ops/s      kB/s     kB/op   retrans   avg RTT (ms)  avg exe (ms)
                   48.818   347.395     7.116  0 (0.0%)          0.464         0.489
  write:            ops/s      kB/s     kB/op   retrans   avg RTT (ms)  avg exe (ms)
                   90.651  1372.200    15.137  0 (0.0%)          0.815         0.881
  

• The script will turn it into this:

• Prerequisites

  • Python3 (should also work for python2.7)
  • python3-matplotlib

• Execution switches and options

  $ ./nfsioplotter.py -h
  usage: nfsioplotter.py [-h] [--devs dev [dev ...]] [--format ext] [--devlist]
                         [--header title] [--debug]
                         input interval
  
  Plot NFS iostat data.
  
  positional arguments:
    input                 nfs-iostat file.
    interval              Interval in seconds.
  
  optional arguments:
    -h, --help            show this help message and exit
    --devs dev [dev ...]  Select NFS mounts to graph (partial names suffice).
    --format ext          png, ps, eps, svg, pdf and onepdf. (default: png)
                          onepdf: produces one file that contains all charts.
    --devlist             List the devices.
    --header title        Title that appears at the top of each chart.
    --debug               Run with debug output.
  

• List device names from the provided nfsiostat output file

  $ ./nfsioplotter.py nfsiostat.txt 5 --devlist
  /db/postgres_archivelog
  /db/postgres_data
  /db/postgres_wal
  /db/postgres_backup
  /db/postgres_config
  

• Plot all devices

  $ ./nfsioplotter.py nfsiostat.txt 5
  

• Plot a couple of devices with a title

  $ ./nfsioplotter.py nfsiostat.txt 5 --devs data wal --header normal
  

• Example of plotting all devices except one

  $ ./nfsioplotter.py nfsiostat.txt 5 --devs $(./nfsioplotter.py nfsiostat.txt 5 --devlist|grep -v backup)
  

• Plot a couple of devices and save to multi-page pdf document

  $ ./nfsioplotter.py nfsiostat.txt 5 --devs data wal --format onepdf
  

Tips

• Joining graphs side-by-side for easy comparision

  for i in avgrtt iops requestsize throughput
  do
    convert dataset1/2931_${i}.png dataset2/14802_${i}.png +append ${i}.png
  done
  

  • With the help of imagemagick tool

  sudo apt install imagemagick-6.q16