What happens with array when external write-intent bitmap fails?

What happens with array when external write-intent bitmap fails?

[Andrei Borzenkov]

Theoretically write-intent is optional, so if it fails it would be
possible to simply discard it and continue. But I have seen statement
that if external write-intent bitmap file is not available at time of
assembly, starting of array fails.

Thank you for clarification.

-andrei

Re: What happens with array when external write-intent bitmap fails?

[NeilBrown]

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On Tue, 16 Sep 2014 17:42:13 +0400 Andrei Borzenkov <arvidjaar@gmail.com>
wrote:

> Theoretically write-intent is optional, so if it fails it would be
> possible to simply discard it and continue. But I have seen statement
> that if external write-intent bitmap file is not available at time of
> assembly, starting of array fails.
> 
> Thank you for clarification.

What exactly did you want clarified?

I suggest the best thing to do is to use "losetup" to create some loop-back
devices.  Then use mdadm to create an array using those devices.
Then simulate the failure mode that you are concerned about and see what
happens.

If you find that the documentation does not agree with reality, please
consider posting details.

Thanks,
NeilBrown

> 
> -andrei
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