title: MySQL: InnoDB buffer pool utilization
catalog: app/mysql
agents: linux
author: Kuhn & Rueß GmbH <info@kuhn-ruess.de>
license: GPL
distribution: none
description:
 Reports the InnoDB buffer pool utilization in percent, calculated as
 {(Innodb_buffer_pool_pages_total - Innodb_buffer_pool_pages_free) /
 Innodb_buffer_pool_pages_total * 100}.

 Both values are collected by the standard Checkmk MySQL agent plugin
 via {SHOW GLOBAL STATUS}, so no additional agent-side configuration
 is required.

 High utilization (>90%) is normal and desirable for production
 databases because a full buffer pool means MySQL caches data
 effectively. Upper thresholds should therefore only be configured
 if persistent saturation at 100% is to be flagged, e.g. as an
 indicator that the buffer pool size needs to be increased.

 The check defaults to always-OK; the ruleset prefills warn/crit at
 95% / 99% as a suggested starting point.

item:
 The MySQL instance name as reported by the MySQL agent section
 (e.g. {mysql}).

inventory:
 One service per MySQL instance is created automatically when both
 {Innodb_buffer_pool_pages_total} and {Innodb_buffer_pool_pages_free}
 are present in the instance section.
