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 DiskMon (getdisk.pl and showdisk.pl)

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by Steven Micallef <smic@wire.net.au>

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What they do

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getdisk.pl and showdisk.pl work on the client/server principal.

showdisk.pl - runs off the 'server' displaying disk partition % used.

getdisk.pl  - runs off the 'client' and connects to the 'server' to get disk

              info off showdisk.pl.

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Before you begin

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Before you Install, you need the following:

- Perl

- Net::Telnet Perl Module.

You can get this straight from:

ftp.oleane.net/pub/CPAN/mirrors/modules/by-module/Net/Net-Telnet-3.01.tar.gz

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Installation

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The following steps apply to EACH MACHINE YOU WANT TO MONITOR...

1. Copy the showdisk.pl script to the host you wish to monitor.

2. In your /etc/inetd.conf, insert the line:

df	stream	tcp	nowait	root	<path of your TCP wrapper>	<path of showdisk.pl>

Of course, the TCP wrapper isn't mandatory, but if you want to restrict access

to the viewing of free disk space, I really recommend you install it.

3. In your /etc/services file, put in the following line:

df	9047/tcp

The port you choose is up to you, but if you do change it from 9047, be sure

to update getdisk.pl too (the port number is specified in the first few lines

of the script).

4. kill -HUP your inetd

5. Test it by telnetting to the host at port 9047. You should get the

following:

bash~# telnet hostname 9047

< usual connect messages >

30

40

10

20

.

.

etc..

Of course, the output depends on

a) how many disks are on the machine, and

b) how much space in % is used on each disk.

If you didn't get any output, go back and make sure you did everything

properly.

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Setting up getdisk.pl with MRTG

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The getdisk.pl script runs like so:

./getdisk.pl <hostname> <disk number>

For example, doing a ./getdisk sparky 1 will show how much % of the first

partition (usually the root partition) on sparky is used.

So how do you map a number to a partition? 

On the host you installed showdisk.pl on, do the following:

bash~# df -k

Filesystem         1024-blocks  Used Available Capacity Mounted on

/dev/hda1             202222   78786   112993     41%   /

/dev/hdc3            2486311 1247138  1110635     53%   /usr

/dev/hdc1            1486150  375570  1033782     27%   /backup

                                                   ^

The first disk is 1, the second 2, and so on..     |

Example:                                           |

  bash~# ./getdisk.pl hostname 3                   |

  27         <-------------------------------------'

Please look at sample.cfg to see how to setup getdisk.pl with MRTG.

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I hope this is as useful to you as it has been to me. If you have any

problems/bug reports/advice/complaints, email me.

Enjoy.

Steven Micallef

<smic@wire.net.au>