This is the native PHP bindings for RRD tool system. Uses native librrd C API.
- PHP PECL extension info - https://pecl.php.net/package/rrd
- PHP usage documentation - https://www.php.net/rrd
- rrd tool - https://oss.oetiker.ch/rrdtool/
- librrd C API - https://oss.oetiker.ch/rrdtool/doc/librrd.en.html