Red Hat Bugzilla – Bug 748986
mdadm starts resync on imsm raid even in Normal state
Last modified: 2012-07-11 03:31:48 EDT
Description of problem:
mdadm starts resync on imsm raid even BIOS reports "Normal" state (this state was the result of a successful sync until last poweroff.
Version-Release number of selected component (if applicable):
(initramfs created using shown mdadm version)
Steps to Reproduce:
2. let resync finish
Resync starts again
# cat /proc/mdstat
Personalities : [raid1]
md127 : active raid1 sda sdb
156288000 blocks super external:/md0/0 [2/2] [UU]
[>....................] resync = 4.9% (7779584/156288132) finish=64.6min speed=38294K/sec
md0 : inactive sdb(S) sda(S)
5544 blocks super external:imsm
related dmesg report:
[ 3.311658] dracut: Autoassembling MD Raid
[ 3.324529] md: md0 stopped.
[ 3.326070] md: bind<sda>
[ 3.326143] md: bind<sdb>
[ 3.326280] dracut: mdadm: Container /dev/md0 has been assembled with 2 drives
[ 3.334575] md: md127 stopped.
[ 3.334724] md: bind<sdb>
[ 3.337308] md: bind<sda>
[ 3.341079] md: raid1 personality registered for level 1
[ 3.343813] bio: create slab <bio-1> at 1
[ 3.346517] md/raid1:md127: not clean -- starting background reconstruction
[ 3.349168] md/raid1:md127: active with 2 out of 2 mirrors
[ 3.351725] md127: detected capacity change from 0 to 160038912000
[ 3.355530] md127: p1 p2 p3 p4 < p5 p6 p7 p8 >
[ 3.482773] md: md127 switched to read-write mode.
[ 3.485360] md: resync of RAID array md127
[ 3.487793] md: minimum _guaranteed_ speed: 1000 KB/sec/disk.
[ 3.490229] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for resync.
[ 3.492691] md: using 128k window, over a total of 156288132k.
[ 3.496305] dracut: mdadm: Started /dev/md127 with 2 devices
Is there any debug information available how to get more information why mdadm is detecting that md127 is not clean while this was reported as "Normal" in the BIOS?
Does this happen both if you are using the RAID for booting from and/or
if you have the RAID as a secondary device and boot off a regular partition?
The RAID is my primary device, I can't easily configure it as second device...no other bootable disks in there.
But it looks like it has to do with the shutdown procedure.
Yesterday, I need to poweroff via Alt-Sysrq (hanging during "unmount", probably related to autofs problem). Now booting today (BIOS-Status: Normal), no resync was triggered. Rebooting now again will result in resync (array detected as "not clean").
My system is too fast to follow last messages before booting, but I thought I have seen on Alt-Sysrq-Poweroff something like "raid status stored", while on reboot, nothing such was seen.
Interesting - I was wondering if it was related to shutdown. The problem with
BIOS RAID is that the kernel cannot do the full shutdown on it's own, so if
something is hanging and preventing mdadm/mdmon from doing their job, it could
result in some of the RAID metadata not being written out as it should.
So, next normal shutdown triggered and power-on again -> resync starts again.
For me it looks like only Alt-Sysrq-Poweroff will leave a synced RAID in proper state for next power-on.
Normal power-off or reboot won't. Any suggestions for debugging this deeper?
I am also having this issue on Fedora 16. The system was running Fedora 15 and was upgraded to 16. Something happen in Fedora 15 that was causing it to not boot correctly. I went ahead and upgraded to 16. It went smooth except for this issue.
Fedora 15 has reached end of life, so we'll continue to investigate this
problem in the Fedora 17 bugzilla #753335