How to visualize used disk space in your storage pool

Greyhole 0.15 and later includes a full admin web UI, which includes disk space visualization.
The information below is now deprecated, and only relevant for version 0.14 and earlier.

Requirements

If you are using PHP 5.3 or earlier: You will need Apache and PHP installed on your Greyhole server to use this script.
With PHP 5.4+, you need nothing.

Install

1. Make /usr/share/greyhole/web-app/ available through HTTP. For example, you could edit your Apache config to alias /usr/share/greyhole/web-app/ to the gh-du virtual folder.
   If you're using PHP 5.4+, you don't even need a web server. Just start the PHP built-in server, and specify the path to the index.php script: php -S 0.0.0.0:8012 /usr/share/greyhole/web-app/index.php
2. Stats used to display the graph are gathered once a week, when the cron-scheduled fsck runs (usually Sunday mornings). If you'd like to refresh the data, run the following command: greyhole --fsck --email-report --dont-walk-metadata-store --disk-usage-report, and wait until you receive the email reports for all your shares. (If your server can't send emails from the command line, I suggest you fix that ASAP, as Greyhole will sometimes send you email alerts that you'll want to receive.)

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Then simply access the script using your web browser, and you should see a nice visual representation of the disk space used by your files.

If you used php -S, access it at http://your_server_ip_address:8012/

Note that all file copies are counted, so if your Videos share shows as 2TB, and you have num_copies=2 for that share, it means you have 1TB of Videos files x 2 copies = 2TB.

Screenshot: