Incorrect VM IOPS metrics

### problem

VM metrics show incorrect IOPS. This may be related to the type of my primary storage. I’m using Linstor. When we perform a fio test, we get the following results:

But VM metrics shows in this time:

### versions

ACS 4.19.3
Primary storage - Linstor 1.31.3
OS: Ubuntu 24.04.2

### The steps to reproduce the bug

Just perform a fio test and check the metrics.

### What to do about it?

It would be great if this metric could be fixed.

Reproduce the fio test against Apache CloudStack 4.19.3 with Linstor 1.31.3 on Ubuntu 24.04.2, then compare the fio results with the VM IOPS metrics over the same interval. Trace the metric calculation from the VM metrics entry point; done means the reported IOPS match the observed storage results.

Written by the indexing model from the issue text.