[Lustre-discuss] Moving MGS to separate device

[Bernd Schubert]

Hello Wojciech,

I already did this several times, here are the steps I so far used:

1) Remove MGS from MDT-device

tunefs.lustre --nogms /dec/mdt_device

2) Create new MGS

mkfs.lustre --mgs /dev/mgs_device

3) Make sure OSTs and  MDTs re-register with the MGS:

tunefs.lustre --writeconf  /dev/device

I'm not sure if writeconf is really necessary, but so far I always did it to 
make sure everything goes smoothly (clients shouldn't have the filesystem 
mounted at this step).

5) Mount MGS, MDT, OSTs

4) Re-apply settings done with lctl.


As you also wrote (private mail), it might be possible to just copy over the 
CONFIGS directory, but I never tried to do that.



Hope it helps,
Bernd



On Saturday 10 October 2009, Wojciech Turek wrote:
> Hi,
> 
> I am very interested in finding out how to move co-located MGS to separate
> disk. I will be moving my MDTs to new hardware soon and I would like to
> separate MGS from MDT. I will be grateful for some info on this subject
> please.
> 
> Many thanks,
> 
> Wojciech
> 
> 2008/6/23 Andreas Dilger <adilger at sun.com>
> 
> > On Jun 17, 2008  12:40 -0700, Klaus Steden wrote:
> > > I have a question ... if the MGS is used so infrequently relative to
> > > the
> >
> > use
> >
> > > of the MDS, why is it (is it?) problematic to locate it on the same
> >
> > volume
> >
> > > as the MDT?
> >
> > If you have multiple MDTs on the same MDS node (i.e. multiple Lustre
> > filesystems) then it is difficult to start up the MGS separately from
> > the MDT if it is co-located with one of the MDTs.  It isn't impossible
> > (with some manual mounting of the underlying filesystems) to move a
> > co-located MGS to a separate filesystem if needed.
> >
> > Cheers, Andreas
> > --
> > Andreas Dilger
> > Sr. Staff Engineer, Lustre Group
> > Sun Microsystems of Canada, Inc.
> >
> > _______________________________________________
> > Lustre-discuss mailing list
> > Lustre-discuss at lists.lustre.org
> > http://lists.lustre.org/mailman/listinfo/lustre-discuss
> 


-- 
Bernd Schubert
DataDirect Networks