Greetings all, The problem in a nutshell is that an array is clean after boot, until some specific jobs switch it to active where it remains until reboot. A similar problem was discussed, and solved, in https://www.spinics.net/lists/raid/msg46450.html. However, AFAICT, it is not the same issue. I would be grateful for any insights as to why this happens and/or how to prevent it. The relevant info follows, please let me know if anything further might help. Many thanks in advance. - uname -a Linux hostname 4.4.38 #1 SMP Sun Dec 11 16:03:41 CST 2016 x86_64 Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz GenuineIntel GNU/Linux - mdadm -V mdadm - v3.3.4 - 3rd August 2015 - Desktop drives without sct/erc, with timeout mismatch correction as per https://raid.wiki.kernel.org/index.php/Timeout_Mismatch - /dev/md9 is a raid10 array, 4 devices, far=2, with various dirs used as samba and nfs shares - The array is in *constant* array_state active - mdadm -D /dev/md9 | grep 'State :' State : active - cat /sys/block/md9/md/array_state active - watch -d 'grep md9 /proc/diskstats' remain unchanged - uptime load average: 0.00, 0.00, 0.00 - cat /sys/block/md9/md/safe_mode_delay 0.201 - echo 0.1 > /sys/block/md9/md/safe_mode_delay array_state remains active - echo clean > /sys/block/md9/md/array_state echo: write error: Device or resource busy - reboot (with or without prior check) array_state clean - After reboot, array remains clean until some specific jobs put it in constant active state. Such jobs so far identified: - echo check > /sys/block/md9/md/sync_action - run an rsnapshot job - start a qemu/kvm vm - Other jobs, like text/doc editing, multimedia playback, etc retain array_state clean -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html