[Drbd-dev] How Locking in GFS works...

[Philipp Reisner]

On Monday 04 October 2004 16:09, Philipp Reisner wrote:
> On Monday 04 October 2004 15:49, Lars Marowsky-Bree wrote:
> > On 2004-10-04T15:26:15, Philipp Reisner <philipp.reisner at linbit.com> 
wrote:
> > > If everything works (esp. the locking of the shared disk fs) no.
> > >
> > > But just consider that the locking of the shared disk FS on
> > > top of us is broken, and that it issues a write request to
> > > the same block number on both nodes.
> > >
> > > Then each node would write its copy first and the peers
> > > version of the data at second to that block number.
> > >
> > > => We would have different data in this block on our
> > >    two copies. - And we would event know about it!
> >
> > You would know the moment the replicated write from the remote end came
> > in, no?
> >
> > "Oh my, this is dirty locally too and unacked. We better arbitate now;
> > ie one side wins and the other one is silently discarded."
>
> This is what I like about mailinglists. This is a new idea, that
> certainly needs to be considered.
>
> Hmm, I just tooks a sheet of paper and drew a view diagrams of it.
>
> It works as long as writing the block takes longer than transmitting
> the block.
>
> The scheme simply fails if transmitting takes longer than writing.
>

No. It works... I will write a text describing it.

-Philipp

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