Why "load average" doesn't match CPU load?

Question

linux

Good day.
I would be very grateful to you if you tell me how to find out the cause of excessive disk activity and the reason for the "load average" discrepancy with the processor load?
"load average" does not correspond to CPU load:
There are 16 cores on the server, 15 of them are loaded at exactly 0.00%
and only one core at 3.2%
, and yet HTOP shows "Load average: 24.26 20.45 19.59".
Tasks: 262, 194 thr: 1 running
Excessive disk activity:
Zabbix started sending me messages at night
Trigger: Disk I/O is overloaded on L-BETA
Trigger status: PROBLEM
Trigger severity: Warning

Answer 1

Your drive is most likely dead.
It has already been discussed many times, including on the toaster in several topics, I personally answered.
load average (high) is no longer about the real load per percent, but about processes in the D-state (these are processes that are "stuck" due to a disk or network). Considering what happened after the reboot, there is clearly a disk that is very dull and bios does not have time to initialize it during boot.
It is also possible that there is a problem with the disk controller.

Answer 2

habrahabr.ru/post/216827
And if in words:
cpu loading and load average are slightly different things. LA shows how quickly the system can respond to external influences. LA also takes into account internal OS locks (in particular, work with disks and other devices, during which the processor can actually be idle)

Answer 3

After I sent the server to reboot, I lost the connection to it:
Support issued a message:

I would like to inform you that the server hangs at the message
Connecting Boot Devices and Adapters and several minutes later it reboots.

The brain is torn, I can not find a connection between the first problem and the second.