[DRBD-user] Re: [DRBD-dev] RE: [SSI-users] Re: DRBD

Philipp Reisner philipp.reisner at linbit.com
Wed Jan 28 09:15:23 CET 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Hi Bruce,

As Lars pointed already out we are a behind our schedule.
The current status is, that drbd-0.7 works very well on 2.4.x based
kernels by now.
On the Linux-2.6.x side, it compiles by now (but do not try to load the
modlue :).

I will do some testing, and ensure that it _does_ work on 2.4.x 
and release drbd-0.7-pre5 by the end of the week. ( Due to the work
on the 2.6.x integreation a lot of code is in flux )

Of course it is possible that it is not that stable as drbd-0.6.10 is,
but I think it is essential that you base any effort on the newer
code. (Internally there are huge differences between drbd-0.6 and 

Does this sound reasonable ?


> Philipp,
>    Hope you are well and your drbd-0.7 is stable.  We have just put out
> 1.0 of OpenSSI and we have increased interest in having DRBD integrated
> into it. I would propose a 3 step development/test effort:
> a. without any changes to DRBD, try to set up a mirror of a filesystem
>    between say node 2 and node 3;  it would be an ext3 filesystem with
>    CFS transparently stacked on top;  try to shoot the primary node
>    and transparently failover the filesystem to node the other node.
>    This would be wonderful functionality to have;
> b. Try to make the same capability work for the root filesystem,
>    making any necessary changes to OpenSSI or DRBD;
> c. Integrate the membership capabilitites.
> One of the OpenSSI developers successfully tried an earlier version of
> DRBD although I'm not sure he actually tried failing over.
> I think it would make most sense for someone from OpenSSI to initiate the
> integration, with help from the DRBD team.  Is now a good time
> to take a snapshot and try it out?
> thanks,
>    bruce
> [ Charset ISO-8859-1 unsupported, converting... ]
> > Hi Burce,
> >
> > I think we met at that cluster workshop in ... was it Enshede ?
> >
> > [...]
> >
> > >    My thought was that the use of DRBD would allow us to have HA-CFS
> > > but without requiring the shared disk.  Accomplishing this for non-root
> > > filesystems could be a simple integration.   There are callback
> > > interfaces in the kernel from the membership module to each "service".
> > > The membership module is called CLMS and I hope we can figure out how
> > > to interface that to the DRBD code to let DRBD kernel code know when
> > > nodes go up or down.
> >
> > Yes. DRBD, of course has a sort of a membership layer, although it is
> > rather integrated. But I am sure that it will be possible to drop
> > DRBD's membership layer and to rely on SSI's view of the world.
> >
> > > The question for the DRBD development group is whether and how we can
> > > switch from the primary to the secondary copy of the data without
> > > running non-kernel code (it is difficult to run non-kernel code when
> > > failing over the root filesystem)?
> >
> > The name of the fucntion is drbd_set_state(). We just need to make
> > it accessible from other parts of the kernel. -- Yes will will need
> > to write a bit of glue code...
> >
> > > I hope the background makes it clear how we were hoping to integrate
> > > and leverage the two projects.   Being able to simultaneously read the
> > > secondary copy while the primary is active might be a nice extension
> > > but is not at all a requirement at this point.
> >
> > Bruce, we are currently working hard on finishing drbd-0.7, which
> > is a rather big step in drbd's evolution. As soon as drbd-0.7 is
> > stable (we want to be there in November), I want to
> > experiment with openGFS and Oracle's physical parallel file system.
> >
> > As soon as we have drbd-0.7 stable I am ready to help out to
> > integrate DRBD to your work.
> >

: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
: Schönbrunnerstr 244, 1120 Vienna, Austria    http://www.linbit.com :

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