Yes sorry should have sent that output. This is the weird side!
So md0 was unaffected and it assembled perfectly. Here is a sample output from /dev/sdf
/dev/sdf:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : a24f542c:e0bc0fd0:983af76e:c7581724
Name : hulk:0 (local to host hulk)
Creation Time : Wed Aug 15 16:24:17 2012
Raid Level : raid6
Raid Devices : 24
Avail Dev Size : 5860531120 (2794.52 GiB 3000.59 GB)
Array Size : 128931677952 (61479.42 GiB 66013.02 GB)
Used Dev Size : 5860530816 (2794.52 GiB 3000.59 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : c3d3ea5b:7db696fd:71474db6:c07c7415
Update Time : Mon Oct 1 13:54:05 2012
Checksum : 246155dd - correct
Events : 41
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 4
Array State : AAAAAAAAAAAAAAAAAAAAAAAA ('A' == active, '.' == missing)
So this chunk size is 64k. The chunk size of md1 is 4k.
/dev/sdaf:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : ab4c898b:03310a29:276a40a1:2ad45c73
Name : hulk:1 (local to host hulk)
Creation Time : Mon Oct 1 13:51:50 2012
Raid Level : raid6
Raid Devices : 19
Avail Dev Size : 5860531120 (2794.52 GiB 3000.59 GB)
Array Size : 99629024416 (47506.82 GiB 51010.06 GB)
Used Dev Size : 5860530848 (2794.52 GiB 3000.59 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 0a88e45f:7df6b724:59825715:faf4abdf
Update Time : Mon Oct 1 13:54:05 2012
Checksum : b276ec79 - correct
Events : 2
Layout : left-symmetric
Chunk Size : 4K
Device Role : Active device 5
Array State : AAAAAAAAAAAAAAAAAAA ('A' == active, '.' == missing)
I created these arrays using webmin and I guess I must have left the default which is 4k in that tool. I manually changed md0 and md2 to 64k when I created those arrays.
However here is the weird part. This is the output of md0 which was the array that built perfectly upon reboot.
/dev/md0:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : aaa29f43:b689f66d:f270c5fc:405620b7
Name : hulk:2 (local to host hulk)
Creation Time : Wed Aug 15 16:26:09 2012
Raid Level : -unknown-
Raid Devices : 0
Avail Dev Size : 128931675904 (61479.42 GiB 66013.02 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : active
Device UUID : b626dd72:995f1277:6f61e94a:489e0468
Update Time : Sat Sep 29 14:49:09 2012
Checksum : c09051e9 - correct
Events : 1
Device Role : spare
Array State : ('A' == active, '.' == missing)
And this is the output of md1 AFTER the recreation.
/dev/md1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : aaa29f43:b689f66d:f270c5fc:405620b7
Name : hulk:2 (local to host hulk)
Creation Time : Wed Aug 15 16:26:09 2012
Raid Level : raid0
Raid Devices : 2
Avail Dev Size : 99629022368 (47506.82 GiB 51010.06 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 184bb4db:b77d921f:28a45e09:dc58e1e1
Update Time : Wed Aug 15 16:26:09 2012
Checksum : 334e56ee - correct
Events : 0
Chunk Size : 64K
Device Role : Active device 1
Array State : AA ('A' == active, '.' == missing)
So I am now thinking that during my shutdown this weekend the device /dev/md0 as part of the array /dev/md2 was affected by the bug as well as 18 of the 19 devices contained inside of /devm/md1
Mark Munoz
On Oct 1, 2012, at 6:49 PM, NeilBrown <neilb@xxxxxxx> wrote:
> On Mon, 1 Oct 2012 14:00:24 -0700 Mark Munoz <mark.munoz@xxxxxxxxxxxxxxxxxxx>
> wrote:
>
>> Neil,
>>
>> Thank you again so much for taking time out of your day to personally help me it really means a lot. I have ran the command and have successfully recreated my md1 Now however md2 will not assemble. I get this error.
>
> Please don't take the discussion off-list.
>
> If you want an answer, you will have to post to the list - and CC me if you
> like.
>
> NeilBrown
>
>
>>
>> sudo mdadm --assemble --force /dev/md2 /dev/md0 /dev/md1
>> mdadm: superblock on /dev/md1 doesn't match others - assembly aborted
>>
>> Would I be correct in thinking that I just need to recreate md2 now as well?
>>
>> I assume with this command?
>>
>> sudo mdadm --create --assume-clean /dev/md2 --level=0 --chunk=64 --metadata=1.2 --raid-devices=2 /dev/md0 /dev/md1
>>
>> Mark Munoz
>>
>> On Sep 30, 2012, at 8:02 PM, NeilBrown <neilb@xxxxxxx> wrote:
>>
>>> On Sat, 29 Sep 2012 17:12:40 -0700 Mark Munoz
>>> <mark.munoz@xxxxxxxxxxxxxxxxxxx> wrote:
>>>
>>>> Hi I appear to have been affected by the bug you found on 7/15/12. The data I have on this array is really important and I want to make sure I get this correct before I actually make changes.
>>>>
>>>> Configuration:
>>>> md0 is a RAID 6 volume with 24 devices and 1 spare. It is working fine and was unaffected.
>>>> md1 is a RAID 6 volume with 19 devices and 1 spare. It was affected. All the drives show as unknown raid level and 0 devices. With the exception of device 5. It has all the information.
>>>>
>>>> Here is the output from that drive:
>>>>
>>>> serveradmin@hulk:/etc/mdadm$ sudo mdadm --examine /dev/sdaf
>>>> /dev/sdaf:
>>>> Magic : a92b4efc
>>>> Version : 1.2
>>>> Feature Map : 0x0
>>>> Array UUID : 6afb3306:144cec30:1b2d1a19:3a56f0d3
>>>> Name : hulk:1 (local to host hulk)
>>>> Creation Time : Wed Aug 15 16:25:30 2012
>>>> Raid Level : raid6
>>>> Raid Devices : 19
>>>>
>>>> Avail Dev Size : 5860531120 (2794.52 GiB 3000.59 GB)
>>>> Array Size : 99629024416 (47506.82 GiB 51010.06 GB)
>>>> Used Dev Size : 5860530848 (2794.52 GiB 3000.59 GB)
>>>> Data Offset : 2048 sectors
>>>> Super Offset : 8 sectors
>>>> State : clean
>>>> Device UUID : 205dfd9f:9be2b9ca:1f775974:fb1b742c
>>>>
>>>> Update Time : Sat Sep 29 12:22:51 2012
>>>> Checksum : 9f164d8e - correct
>>>> Events : 38
>>>>
>>>> Layout : left-symmetric
>>>> Chunk Size : 4K
>>>>
>>>> Device Role : Active device 5
>>>> Array State : AAAAAAAAAAAAAAAAAAA ('A' == active, '.' == missing)
>>>>
>>>> Now I also have md2 which is a striped RAID of both md0 and md1.
>>>>
>>>> When I type:
>>>>
>>>> sudo mdadm --create --assume-clean /dev/md1 --level=6 --chunk=4 --metadata=1.2 --raid-devices=19 /dev/sdaa /dev/sdab /dev/sdac /dev/sdad /dev/sdae /dev/sdaf /dev/sdag /dev/sdah /dev/sdai /dev/sdaj /dev/sdak /dev/sdal /dev/sdam /dev/sdan /dev/sdao /dev/sdap /dev/sdaq /dev/sdar /dev/sdas
>>>>
>>>> the following error for each device.
>>>>
>>>> mdadm: /dev/sdaa appears to be part of a raid array:
>>>> level=-unknown- devices=0 ctime=Wed Aug 15 16:25:30 2012
>>>> mdadm: partition table exists on /dev/sdaa but will be lost or
>>>> meaningless after creating array
>>>>
>>>> I want to make sure by running this above command that I won't affect any of the data of md2 when I assemble that array after creating md1. Any help on this issue would be greatly appreciated. I would normally just DD copies but as you can see I would have to buy 19 more 3TB hard drives as well as the time to DD each drive. It is a production server and that kind of down time would really rather be avoided.
>>>
>>> Running this command will only overwrite the 4K of metadata, 4K from the
>>> start of the devices. It will not write anything else to any device.
>>>
>>> so yes, it is safe.
>>>
>>> NeilBrown
>>>
>>>
>>>
>>>>
>>>> Thank you so much for your time.
>>>>
>>>> Mark Munoz
>>>> 623.523.3201--
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>>>
>
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