Physical Disk

This Check may be used when analyzing the disk subsystem including the disk controller, the I/O bus and the disk itself including any partitions, and indicates the overall performance of the disk.

This Check includes three components that are sampled every 5 seconds:

• Average Read Queue Length: the average queue length for the read requests issued to the device.
• Average Write Queue Length: an average queue length for the write requests issued to the device.
• Average Percentage Disk Time: the percentage of time the disk is busy with read/write activity.

Thresholds

From Dashboard 2020.01.20 we updated the default threshold values for new Checks. Existing Check thresholds are unaffected.

Threshold	Pre-2020.01.2 Threshold	Threshold from 2020.01.2
Alert if average read queue length >	2	4
Alert if average read queue length >	2	4
Alert if average read queue length >	50%	85%