ERROR: No DS called 'value' in ... disk_io_time.rrd' about cgp

[Orabig]

I've got the same issue, and finally found a solution.
You certainly has a data_type line in /etc/collectd/my_types.db , included in /etc/collectd/collectd.conf (TypesDB parameter) defining these metrics, with this content :

disk         io_time:DERIVE:0:U, weighted_io_time:DERIVE:0:U

You must :

• Copy this file to /usr/www/<your_CGP_root>/inc/my_types.db
• Add the following line in your config file /usr/www/<your_CGP_root>/conf/config.local.php :

$CONFIG['typesdb'][] = 'inc/my_types.db';

Note : unfortunately, you cannot use an absolute path here, thus have a direct reference to the file (which is used by collected) located in /etc/collectd/ will not work.