[dm-devel] [RFC][PATCH] dm-mirror: fix data corruption
Takahiro Yasui
tyasui at redhat.com
Fri Jul 10 19:14:40 UTC 2009
Hi Nomura-san,
On 07/10/09 07:16, Jun'ichi Nomura wrote:
> Hi Yasui-san,
>
> Takahiro Yasui wrote:
>> This is a prototype patch to fix data corruption issue on dm-raid1.
>> It is just a draft patch and is not tested well, but let me post it
>> to review and discuss this in-kernel superblock approach.
>>
>> I appreciate your comments and suggestions.
> <snip>
>> * Introduce superblock area
>>
>> A superblock area is related to a mirror leg on a one-to-one basis and
>> keeps a sequential number to decide the default mirror when the mirror
>> is resumed.
>
> If you are to introduce kernel-managed RAID1 superblock,
> isn't it possible to use the on-disk format compatible to md's?
> Then the kernel code to handle the superblock may be shared between
> md and dm in future, which I think is even better and would help
> dm/md convergence.
Thank you for the comment. You are right and sharing the kernel code to
handle superblock between md and dm would be better toward merging dm/md.
I would like to introduce this in-kernel superblock approach, but userspace
approach handled by dmeventd seems to be preferred. I try to check the
possibility to reduce overhead of error handling in userspace.
Thanks,
Taka
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