when md raid1 superblock is bad block, what happens

when md raid1 superblock is bad block, what happens

[archer.wudong]

hi all, I have some questions about raid1 superblock and bad block.
when i create raid1 with two disks, the md will write superblock to the disk, if the location of superblock is bad , what will happens? report create error or add the block to bad-block-list and redirect superblock to another place?
another question, how many bad blocks can be added to bad-block-list, when the bad-block-list is full, the raid will degrade?

Thank You
Wu Dong

when md raid1 superblock is bad block, what happens

[Dong Wu]

Hi all, I have some questions about raid1 superblock and bad block.
When I create raid1 with two disks, the md will write superblock to
the disk, if the location of superblock is bad, what will happens?
Just report create error or add the block to bad-block-list and
redirect superblock to another place?
another question, how many bad blocks can be added to bad-block-list,
when the bad-block-list is full, the raid will degrade?

Thand you

Wu Dong

Re: when md raid1 superblock is bad block, what happens

[NeilBrown]

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On Tue, 6 Aug 2013 09:14:05 +0800 Dong Wu <archer.wudong@gmail.com> wrote:

> Hi all, I have some questions about raid1 superblock and bad block.
> When I create raid1 with two disks, the md will write superblock to
> the disk, if the location of superblock is bad, what will happens?

The drive will be removed from the array.

> Just report create error or add the block to bad-block-list and
> redirect superblock to another place?

No.  That would be nice but it isn't implemented.

> another question, how many bad blocks can be added to bad-block-list,
> when the bad-block-list is full, the raid will degrade?

512 ranges of badblocks.  When it is full the array will degrade.

NeilBrown


> 
> Thand you
> 
> Wu Dong
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Re: when md raid1 superblock is bad block, what happens

[Roberto Spadim]

another question, that i'm thinking now after this email...
i never read about, but... what's the size of super block?
could it be mirrored inside the disk like a raid1 inside the device
being used? if the first image of superblock is broken try to read the
next one