Thank you Neil for the reply and heads-up on 3.1.3. I will test that
immediately and report back my findings.
One potential issue I noticed is that Ubuntu Lucid's default kernel
configuration has CONFIG_MD_AUTODETECT enabled. I thought this feature
might conflict with udev, so I've attempted to disable this by adding
a parameter to my grub2 bootup: raid=noautodetect. But I am not sure
if this is effective. Do you think this kernel setting could also be a
problem source?
Another method I was contemplating to avoid a potential locking issue
is to have udev's mdadm -i command run with watershed, which should in
theory serialize it. What do you think?
SUBSYSTEM=="block", ACTION=="add|change", ENV{ID_FS_TYPE}=="linux_raid*", \
RUN+="watershed -i mdadm /sbin/mdadm --incremental $env{DEVNAME}"
Finally, in your view, is it essential that the underlying partitions
used in the md's be the "Linux raid autodetect" type? My partitions at
the moment are just plain "Linux".
Anyway, I will test mdadm 3.1.3 right now but I wanted to ask for your
insight/comments on the above. Thanks!
Best,
Tommy
On Sun, Aug 8, 2010 at 1:58 AM, Neil Brown <neilb@xxxxxxx> wrote:
> On Sat, 7 Aug 2010 18:27:58 -0700
> "fibreraid@xxxxxxxxx" <fibreraid@xxxxxxxxx> wrote:
>
>> Hi all,
>>
>> I am facing a serious issue with md's on my Ubuntu 10.04 64-bit
>> server. I am using mdadm 3.1.2. The system has 40 drives in it, and
>> there are 10 md devices, which are a combination of RAID 0, 1, 5, 6,
>> and 10 levels. The drives are connected via LSI SAS adapters in
>> external SAS JBODs.
>>
>> When I boot the system, about 50% of the time, the md's will not come
>> up correctly. Instead of md0-md9 being active, some or all will be
>> inactive and there will be new md's like md127, md126, md125, etc.
>
> Sounds like a locking problem - udev is calling "mdadm -I" on each device and
> might call some in parallel. mdadm needs to serialise things to ensure this
> sort of confusion doesn't happen.
>
> It is possible that this is fixed in the just-released mdadm-3.1.3. If you
> could test and and see if it makes a difference that would help a lot.
>
> Thanks,
> NeilBrown
>
>>
>> Here is the output of /proc/mdstat when all md's come up correctly:
>>
>>
>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
>> [raid4] [raid10]
>> md0 : active raid6 sdj1[6] sdk1[7] sdf1[2] sdb1[10] sdg1[3] sdl1[8](S)
>> sdh1[4] sdm1[9] sde1[1] sdi1[12](S) sdc1[11] sdd1[0]
>> 1146967040 blocks super 1.2 level 6, 128k chunk, algorithm 2
>> [10/10] [UUUUUUUUUU]
>>
>> md9 : active raid0 sdao1[1] sdan1[0]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md8 : active raid0 sdam1[1] sdal1[0]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md7 : active raid0 sdak1[1] sdaj1[0]
>> 976765888 blocks super 1.2 4k chunks
>>
>> md6 : active raid0 sdai1[1] sdah1[0]
>> 976765696 blocks super 1.2 128k chunks
>>
>> md5 : active raid0 sdag1[1] sdaf1[0]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md4 : active raid0 sdae1[1] sdad1[0]
>> 976765888 blocks super 1.2 32k chunks
>>
>> md3 : active raid1 sdac1[1] sdab1[0]
>> 195357272 blocks super 1.2 [2/2] [UU]
>>
>> md2 : active raid0 sdaa1[0] sdz1[1]
>> 62490672 blocks super 1.2 4k chunks
>>
>> md1 : active raid5 sdy1[10] sdx1[9] sdw1[8] sdv1[7] sdu1[6] sdt1[5]
>> sds1[4] sdr1[3] sdq1[2] sdp1[11](S) sdo1[1] sdn1[0]
>> 2929601120 blocks super 1.2 level 5, 16k chunk, algorithm 2
>> [11/11] [UUUUUUUUUUU]
>>
>> unused devices: <none>
>>
>>
>> --------------------------------------------------------------------------------------------------------------------------
>>
>>
>> Here are several examples of when they do not come up correctly.
>> Again, I am not making any configuration changes; I just reboot the
>> system and check /proc/mdstat several minutes after it is fully
>> booted.
>>
>>
>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
>> [raid4] [raid10]
>> md124 : inactive sdam1[1](S)
>> 488382944 blocks super 1.2
>>
>> md125 : inactive sdag1[1](S)
>> 488382944 blocks super 1.2
>>
>> md7 : active raid0 sdaj1[0] sdak1[1]
>> 976765888 blocks super 1.2 4k chunks
>>
>> md126 : inactive sdw1[8](S) sdn1[0](S) sdo1[1](S) sdu1[6](S)
>> sdq1[2](S) sdx1[9](S)
>> 1757761512 blocks super 1.2
>>
>> md9 : active raid0 sdan1[0] sdao1[1]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md6 : inactive sdah1[0](S)
>> 488382944 blocks super 1.2
>>
>> md4 : inactive sdae1[1](S)
>> 488382944 blocks super 1.2
>>
>> md8 : inactive sdal1[0](S)
>> 488382944 blocks super 1.2
>>
>> md127 : inactive sdg1[3](S) sdl1[8](S) sdc1[11](S) sdi1[12](S)
>> sdf1[2](S) sdb1[10](S)
>> 860226027 blocks super 1.2
>>
>> md5 : inactive sdaf1[0](S)
>> 488382944 blocks super 1.2
>>
>> md1 : inactive sdr1[3](S) sdp1[11](S) sdt1[5](S) sds1[4](S)
>> sdy1[10](S) sdv1[7](S)
>> 1757761512 blocks super 1.2
>>
>> md0 : inactive sde1[1](S) sdh1[4](S) sdm1[9](S) sdj1[6](S) sdd1[0](S) sdk1[7](S)
>> 860226027 blocks super 1.2
>>
>> md3 : inactive sdab1[0](S)
>> 195357344 blocks super 1.2
>>
>> md2 : active raid0 sdaa1[0] sdz1[1]
>> 62490672 blocks super 1.2 4k chunks
>>
>> unused devices: <none>
>>
>>
>> ---------------------------------------------------------------------------------------------------------------------------
>>
>>
>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
>> [raid4] [raid10]
>> md126 : inactive sdaf1[0](S)
>> 488382944 blocks super 1.2
>>
>> md127 : inactive sdae1[1](S)
>> 488382944 blocks super 1.2
>>
>> md9 : active raid0 sdan1[0] sdao1[1]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md7 : active raid0 sdaj1[0] sdak1[1]
>> 976765888 blocks super 1.2 4k chunks
>>
>> md4 : inactive sdad1[0](S)
>> 488382944 blocks super 1.2
>>
>> md6 : active raid0 sdah1[0] sdai1[1]
>> 976765696 blocks super 1.2 128k chunks
>>
>> md8 : active raid0 sdam1[1] sdal1[0]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md5 : inactive sdag1[1](S)
>> 488382944 blocks super 1.2
>>
>> md0 : active raid6 sdc1[11] sdd1[0] sdh1[4] sdf1[2] sdm1[9] sde1[1]
>> sdb1[10] sdg1[3] sdl1[8](S) sdj1[6] sdk1[7] sdi1[12](S)
>> 1146967040 blocks super 1.2 level 6, 128k chunk, algorithm 2
>> [10/10] [UUUUUUUUUU]
>>
>> md1 : active raid5 sdq1[2] sdy1[10] sdv1[7] sdn1[0] sdt1[5] sdw1[8]
>> sdp1[11](S) sdr1[3] sdu1[6] sdx1[9] sdo1[1] sds1[4]
>> 2929601120 blocks super 1.2 level 5, 16k chunk, algorithm 2
>> [11/11] [UUUUUUUUUUU]
>>
>> md3 : active raid1 sdac1[1] sdab1[0]
>> 195357272 blocks super 1.2 [2/2] [UU]
>>
>> md2 : active raid0 sdz1[1] sdaa1[0]
>> 62490672 blocks super 1.2 4k chunks
>>
>> unused devices: <none>
>>
>>
>> --------------------------------------------------------------------------------------------------------------------------
>>
>>
>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
>> [raid4] [raid10]
>> md127 : inactive sdab1[0](S)
>> 195357344 blocks super 1.2
>>
>> md4 : active raid0 sdad1[0] sdae1[1]
>> 976765888 blocks super 1.2 32k chunks
>>
>> md7 : active raid0 sdak1[1] sdaj1[0]
>> 976765888 blocks super 1.2 4k chunks
>>
>> md8 : active raid0 sdam1[1] sdal1[0]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md6 : active raid0 sdah1[0] sdai1[1]
>> 976765696 blocks super 1.2 128k chunks
>>
>> md9 : active raid0 sdao1[1] sdan1[0]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md5 : active raid0 sdaf1[0] sdag1[1]
>> 976765440 blocks super 1.2 256k chunks
>>
>> md1 : active raid5 sdy1[10] sdv1[7] sdu1[6] sds1[4] sdq1[2]
>> sdp1[11](S) sdt1[5] sdo1[1] sdx1[9] sdr1[3] sdw1[8] sdn1[0]
>> 2929601120 blocks super 1.2 level 5, 16k chunk, algorithm 2
>> [11/11] [UUUUUUUUUUU]
>>
>> md0 : active raid6 sdl1[8](S) sdd1[0] sdc1[11] sdg1[3] sdk1[7] sde1[1]
>> sdm1[9] sdb1[10] sdi1[12](S) sdh1[4] sdf1[2] sdj1[6]
>> 1146967040 blocks super 1.2 level 6, 128k chunk, algorithm 2
>> [10/10] [UUUUUUUUUU]
>>
>> md3 : inactive sdac1[1](S)
>> 195357344 blocks super 1.2
>>
>> md2 : active raid0 sdz1[1] sdaa1[0]
>> 62490672 blocks super 1.2 4k chunks
>>
>> unused devices: <none>
>>
>>
>>
>> My mdadm.conf file is as follows:
>>
>>
>> # mdadm.conf
>> #
>> # Please refer to mdadm.conf(5) for information about this file.
>> #
>>
>> # by default, scan all partitions (/proc/partitions) for MD superblocks.
>> # alternatively, specify devices to scan, using wildcards if desired.
>> DEVICE partitions
>>
>> # auto-create devices with Debian standard permissions
>> CREATE owner=root group=disk mode=0660 auto=yes
>>
>> # automatically tag new arrays as belonging to the local system
>> HOMEHOST <system>
>>
>> # instruct the monitoring daemon where to send mail alerts
>> MAILADDR root
>>
>> # definitions of existing MD arrays
>>
>> # This file was auto-generated on Sun, 13 Jul 2008 20:42:57 -0500
>> # by mkconf $Id$
>>
>>
>>
>>
>> Any insight would be greatly appreciated. This is a big problem as it
>> is now. Thank you very much in advance!
>>
>> Best,
>> -Tommy
>> --
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