> > > > Are these captured back to back? I am asking because they showed different > > "Events" number. > > Nah, they were captured between reboots. Back to back all event fields show identical value (at 56291 now). > > > > > Also, when mdadm -A hangs, could you please capture /proc/$(pidof mdadm)/stack ? > > > > The output is empty: > > xs22:/☠ ps -eF fww | grep mdadm > root 10332 9362 97 740 1884 25 12:47 pts/1 R+ 6:59 | \_ mdadm -A /dev/md/r5_big /dev/md/r1_journal_big /dev/sdi1 /dev/sdg1 /dev/sdj1 /dev/sdh1 > xs22:/☠ cd /proc/10332 > xs22:/proc/10332☠ cat stack > xs22:/proc/10332☠ Hmm... Could you please share the strace output of "mdadm -A" command? Like strace mdadm -A /dev/md/r5_big /dev/md/r1_journal_big /dev/xxx ... Thanks, Song