Disk I/O Check Reference

All parameters, thresholds, and configuration options for the disk I/O check in octoja.

Written By Erdinc Akay

Last updated About 1 month ago

Disk I/O Check Reference

The Disk I/O Check measures disk utilization by sampling I/O activity and warns when utilization exceeds the configured thresholds.

Configuration fields

FieldTypeRequiredDefaultDescription
Sampling duration (seconds)SecondsNo2Duration of the I/O activity sampling window (valid range: 1–30 seconds; out-of-range values are clamped at runtime)
Warning utilization (%)PercentNo80I/O utilization that triggers a warning
Critical utilization (%)PercentNo95I/O utilization that triggers a critical result
Exclude disksList of stringsNo—Disks to exclude from monitoring. Matching is case-insensitive substring against the disk identifier (e.g. loop, usb, sr0)

The check runs on a fixed interval of 5 minutes; the interval is not a configurable field in the check editor.

Collected metrics

  • I/O utilization percentage per disk
  • Read throughput (bytes/sec; the UI auto-scales the displayed unit)
  • Write throughput (bytes/sec; the UI auto-scales the displayed unit)

Platform support

PlatformSupported
WindowsYes
LinuxYes
macOSPartial — utilization percent is not available (reported as null); read and write throughput are reported as 0 because iostat on macOS does not expose a read/write split or busy time

Notes

  • The check takes a short I/O sample at each interval. Results reflect the load during that sample, not sustained averages.
  • If the warning threshold is configured higher than the critical threshold, the two values are automatically swapped at runtime so warning is always the lower bound.
  • On Linux, virtual and partition devices are skipped automatically: loop devices (loop*), ramdisks (ram*), device-mapper entries (dm-*), and partitions of a parent disk are filtered out so only physical disks are reported.

See also: Configure a Disk I/O Check