On Mon, Oct 29, 2018 at 2:49 PM Niels de Vos <ndevos@xxxxxxxxxx> wrote:
On Mon, Oct 29, 2018 at 12:06:53PM +0530, Susant Palai wrote:
> On Fri, Oct 26, 2018 at 6:22 PM Niels de Vos <ndevos@xxxxxxxxxx> wrote:
>
> > On Fri, Oct 26, 2018 at 05:54:28PM +0530, Susant Palai wrote:
> > > Hi,
> > > For ALUA in Gluster-Block, we need fencing support from GlusterFS.
> > This
> > > is targeted mainly to avoid corruption issues during fail-over from
> > > INITIATOR.
> > >
> > > You can find the problem statement, design document at [1] and the GitHub
> > > discussions at [2].
> > >
> > > Requesting your feedback on the same.
> >
> > From a quick glance, this looks very much like leases/delegations that
> > have been added for Samba and NFS-Ganesha. Can you explain why using
> > that is not sufficient?
> >
> Niels, is it that you are suggesting leases/delegations already solves the
> problem we are trying to solve mentioned in the design document or just the
> mandatory lock part?
I would be interested to know if you can use leases/delegations to solve
the issue. If you can not, can leases/delegations be extended instead of
proposing an new API?
From what I understand Block-D keeps all the file open bfore beginning of the session (exporting file as block devices). Which I guess won't work with lease, since
lease I guess(please correct me if wrong) breaks the existing lease on an open request. Certainly, with selfheal daemon the lease will be released. Hence, mandatory lock fits here IMO.
@Kalever, Prasanna Please give your feedback here.
>From theory, the high-available NFS-Ganesha and Samba services should
have solved similar problems already.
From what I understand the multipath layer does not have any control over restarting tcmu-runner on Gluster side (If that is how NFS_Ganesha and Samba provides blacklist for it's clients).
The targetcli does certain tasks only on failover switch which would be like taking mandatory lock, open a session as mentioned in the design doc. Hence, no control over data cached at Gluster-client layer to be replayed in the event of a disconnection.
Again @Kalever, Prasanna and @Xiubo Li will be able to clarify more here.
IIRC Anoop CS And Soumya have been working on this mostly. If you have
specific questions about the implementation in Samba or NFS-Ganesha, ask
on this list and include them on CC.
Also, we do have the (low-volume) integration@xxxxxxxxxxx list for
discussions around integrating gfapi with other projects. There might be
others that are interested in these kind of details.
Thanks,
Niels
>
> >
> > Thanks,
> > Niels
> >
> >
> > >
> > > Thanks,
> > > Susant/Amar/Shyam/Prasanna/Xiubo
> > >
> > >
> > >
> > > [1]
> > >
> > https://docs.google.com/document/d/1up5egL9SxmVKFpZMUEuuYML6xS2mNmBGzyZbMaw1fl0/edit?usp=sharing
> > > [2]
> > >
> > https://github.com/gluster/gluster-block/issues/53#issuecomment-432924044
> >
> > > _______________________________________________
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> > > Gluster-devel@xxxxxxxxxxx
> > > https://lists.gluster.org/mailman/listinfo/gluster-devel
> >
> >
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