Hi Neil,
On Mon, Sep 15, 2014 at 05:00:37PM +1000, NeilBrown wrote:
> On Mon, 15 Sep 2014 06:47:41 +0000 Andy Smith <andy@xxxxxxxxxxxxxx> wrote:
> > The thing is, that bug report is quite old and is marked closed, and
> > also states:
> >
> > "The problem is that 0.9x metadata block doesn't have enough
> > info to check it. With 1.x we have no such problem."
> >
> > Of course, it *is* 1.x superblock. Did the poster actually mean to
> > say that they have no problem with v1.1 and v1.2 (because they are
> > located at or near the beginning of the device, not at the end)?
>
> 0.90 has the problem, 1.x doesn't.
Right.
> Maybe there is an old 0.90 superblock confusing things. It lives in a
> different location than the others and so there is room for confusion.
I think that must be it.
> mdadm --examine --metadata=0.90 /dev/sda3
>
> which show you the 0.90 metadata if there is any.
/dev/sda3:
Magic : a92b4efc
Version : 0.90.01
UUID : 3905b303:ca604b72:be5949c4:ab051b7a
Creation Time : Sun Jun 4 08:18:58 2006
Raid Level : raid10
Used Dev Size : 309363264 (295.03 GiB 316.79 GB)
Array Size : 928089792 (885.10 GiB 950.36 GB)
Raid Devices : 6
Total Devices : 6
Preferred Minor : 2
Update Time : Sun Aug 24 14:26:50 2014
State : clean
Active Devices : 6
Working Devices : 6
Failed Devices : 0
Spare Devices : 0
Checksum : e613d577 - correct
Events : 312149996
Layout : near=2
Chunk Size : 64K
Number Major Minor RaidDevice State
this 5 8 3 5 active sync /dev/sda3
0 0 8 51 0 active sync /dev/sdd3
1 1 8 67 1 active sync
2 2 8 83 2 active sync
3 3 8 19 3 active sync /dev/sdb3
4 4 8 35 4 active sync /dev/sdc3
5 5 8 3 5 active sync /dev/sda3
This shows the array when it had 6 devices as well, so clearly from
before the metadata update and shrink to 4 devices.
> mdadm --zero-super --metadata=0.90 /dev/sda3
>
> will remove any 0.90 metadata.
Trying that whole the array is running:
mdadm: Couldn't open /dev/sda3 for write - not zeroing
This needs to be done with the array stopped, presumably?
Thanks for the explanation!
Cheers,
Andy
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