ok, that’s interesting. the process id is _not_ mdadm daemon and it looks like the spindown itself is triggering the process. ps ax | grep mdadm 28956 ? Ss 0:00 mdadm --monitor --scan --daemonise --pid-file /var/run/mdadm.pid --syslog grep sda /var/log/messages Sep 12 13:55:04 alina spindown: sda is now inactive. Sep 12 13:55:09 alina kernel: mdadm(29737): READ block 3907028992 on sda (8 sectors) Sep 12 13:55:17 alina kernel: mdadm(29737): READ block 3907029152 on sda (8 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 0 on sda (8 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 3907029167 on sda (1 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 3907029166 on sda (1 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 0 on sda (1 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 0 on sda (1 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 3907029152 on sda (8 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 0 on sda (8 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sectors) Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sectors) Sep 12 13:56:12 alina spindown: sda is now active. here’s the output of blktrace -d /dev/sda during that time. https://dl.dropboxusercontent.com/u/3464720/blktrace.tar.bz2 -- 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