hard drive – the raid does not run – mdadm emits synchronizations?

I have a problem with an archive server that runs a RAID 5. The server is only used every other day. So I wish these discs disappear when there is more activity for a while.

Disclaimer: I understand that running the discs is usually bad practice. I do not ask for advice on the life of a disc. I ask for help on how to make the slowdowns. Thank you.

The file system is ext4. I've increased the ext4 validation interval via the appropriate mount option and verified that there was no activity of jbd2. I've also configured systemd-journald in volatile mode and disabled any other nonessential logging. I have 100% verified that no log file is being written and that no user space process has occurred. IO activity. The exchange is disabled.

Nevertheless, iosnoop displays periodic writes on sectors 2056, 2064, and 2088 of the disks in the array. I suspect that it is there that the superblock or the related information is stored. My theory of work is that mdadm marks the RAID as synchronized or something like that, but I have not provided Google with any relevant information.

Does anyone have an alternative theory or idea about how I can stop IO?

Here is an iosnoop trace for the first disk of the array:

# iosnoop-perf -s -d "8.16"
I / O tracing block. Ctrl-C to finish.
START COMM TYPES OF PID TYPE DEV BLOCK
5068.962692 md0_raid5 249 FF 8.16 18446744073709551615 0 0.35
5068.963054            0 WFS 8.16 2064 4096 21.28
5068.990201 md0_raid5 249 FF 8.16 18446744073709551615 0 0.40
5068.990619            0 WFS 8.16 2056 512 18.70
5069.017432 kworker / 1: 1H 216 FF 8.16 18446744073709551615 0 0.42
5069.017866            0 WFS 8.16 2088 3072 24.86
5069.442687 md0_raid5 249 FF 8.16 18446744073709551615 0 0.40
5069.443104            0 WFS 8.16 2064 4096 7.90
5069.467942 md0_raid5 249 FF 8.16 18446744073709551615 0 0.40
5069.468360            0 WFS 8.16 2056 512 57.62
5074.578771 md0_raid5 249 FF 8.16 18446744073709551615 0 0.41
5074.579195            0 WFS 8.16 2064 4096 21.82
5084.818728 md0_raid5 249 FF 8.16 18446744073709551615 0 0.41
5084.819146            0 WFS 8.16 2088 3072 31.92
5125.794841 md0_raid5 249 FF 8.16 18446744073709551615 0 0.35
5125.795205            0 WFS 8.16 2064 4096 22.49
5125.823437 md0_raid5 249 FF 8.16 18446744073709551615 0 0.41
5125.823855            0 WFS 8.16 2056 512 18.83
5125.850640 kworker / 1: 1H 216 FF 8.16 18446744073709551615 0 0.42
5125.851071            0 WFS 8.16 2080 4096 8.33
5125.859599 kworker / 1: 1H 216 FF 8.16 18446744073709551615 0 0.42
5125.860026            0 WFS 8.16 2064 4096 7.67
5126.146833 md0_raid5 249 FF 8.16 18446744073709551615 0 3.50
5126.150353            0 WFS 8.16 2064 4096 8.98
5126.159498 md0_raid5 249 FF 8.16 18446744073709551615 0 4.39
5126.163913            0 WFS 8.16 2056 512 53.75
5131.410989 md0_raid5 249 FF 8.16 18446744073709551615 0 0.41
5131.411412            0 WFS 8.16 2064 4096 22.99
5141.650858 md0_raid5 249 FF 8.16 18446744073709551615 0 0.41
5141.651276            0 WFS 8.16 2064 4096 16.40
5141.667708            0 FF 8.16 18446744073709551615 0 0.29
5141.668012            0 WFS 8.16 2080 4096 7.95