I am monitoring disk utilization via prometheus-node-exporter which reads /proc/diskstats
My expectation would be that if the block device is 100% busy then the field 7 - time spent reading (ms) will increase 1000 (in miliseconds) per second.
But currently when the disk is busy,the increase is between 1200 - 1800 ms per second.
What could be the cause of this? Thanks.
13 - time spent doing I/Os (ms) is increasing as expected less than 1000ms per second.
the HDD is Seagate ST8000AS0022-1WL17Z Host-Aware SMR Debian Bullseye, kernel version 5.4.0-4-amd64 32GB RAM i5 3570, device structure: sde -> loop1 -> dm-crypt -> Virtual machine Virtio -> ZFS the loop device is used because otherwise dm-crypt doesn't work scheduler mq-deadline