[Gluster-devel] Server-side AFR + Failover and mixed server/client-side AFR

[Krishna Srinivas]

On Tue, May 6, 2008 at 9:04 PM,  <gordan at bobich.net> wrote:
> On Tue, 6 May 2008, Krishna Srinivas wrote:
>
>
> >
> > > If server-side AFR breaks with fail-over, is it possible to use
> server-side
> > >
> > > AFR on some nodes and client-side AFR on others, with the client side
> AFR
> > > nodes talking directly to the same storage bricks that the server side
> AFR
> > > is unifying for server-side AFR nodes?
> > >
> > >  Or would this break things?
> > >
> >
> >
> > It will not break things as long as the afr's subvol listing order are
> same.
> >
>
>  Is this an issue in server-side-only AFR? I have two servers which are also
> clients of themselves, and they both list their local subvolume first and
> remote subvolume second. Is this a problem? What are the possible
> consequences of this?

It will be a problem. The "first" subvol is always the "lock" server.
Consider a case where you are creating a file simultaneously
on two clients, only one of them should succeed. If AFR's
subvols order are not same, chances are that both client
returns success for file creation with same name.

Krishna


>
>
>
>  Gordan
>
>
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