[sheepdog] read/write during recovery

[Liu Yuan]

On 07/24/2012 03:27 PM, Dietmar Maurer wrote:
> When the gateway writes 'obj'
> 
> 1.) write 'obj' to C => write a journal, succeed

where is this journal stored? locally in node C?

> 2.) write 'obj' to A => succeed
> 
> Then node C recovers 'obj' from node A. After that, node C need
> to apply above write journal to 'obj' - just to make sure that
> we do not lose any writes.

This scheme might work, but I think with full implementation out, it
would be not simpler than current implementation and need considerable
lines of code. But before we see the real code, we can't reach any
conclusion.

This scheme is kind of radical change, so before this, we can try other
means that need less work, such as beforehand mentioned only recovery of
requested objects instead of all the objects in a given time window,
which is supposed to be useful for maintenance work.

Thanks,
Yuan