Check manual page of diskstat


Disk throughput

Distribution: official part of Check_MK
License: GPL
Supported Agents: Linux, FREEBSD


This check measures the throughput of block devices (disks) on Linux hosts. You can either have a single check for every single disk or a summary check (which is the default) summing up the throughput of all disks.

For legacy reasons it is also possible (but not advisable) to have all disks summarized but with a separate check for read and write (this is how this check worked up to version 1.1.10).

The check also gives info on the IO latency and IOPS (unmerged) aquired from the kernels information in /proc.

You can apply separate warning and critical levels for the read and write throughput. Optionally you can have the check compute average values on a configurable time period and have the levels applied on the average instead of the current values. This makes it possible to ignore short "peaks" and only trigger and longer phases of high disk activity.

Averaging is not applied to IO latency calculations.

The check has to provide many ways of configuration for legacy reasons. We strongly recommend you switch to the rule-based configuration, which handles anything you want it to.

In single disk mode the check now also supports being used in a Check_MK cluster environment. In this case it goes to CRIT if it finds more than one disk item in the cluster. If it finds only one disk item, it also prints the node name the disk was found on.

SUMMARY and legacy read/write modes are not supported in a cluster configuration. The check goes to UNKNOWN and prints an appropriate message if configured like that.

Item

Either "SUMMARY" for a summarized check of all disks or the name of the disk device, e.g. "sda". Additionally also one service per logical volume defined in Linux LVM and Veritas VxVM on Linux.

In order to support configurations up to version 1.1.10 also the items "read" and "write" are supported.

Discovery

The inventory is configured via diskstat_inventory_mode. If this is set to "single" (the default), then one check will be created for each disk. If it is set to "summary" then only one service per host will be created that has at least one hard disk. If set to "legacy" then a separate check for read and write will be created (deprecated).